Construction activity has surged at a deeply buried complex near Iran’s Natanz nuclear facility, but satellite evidence suggests the site may not yet be capable of uranium enrichment, according to a new analysis by the Center for Strategic and International Studies.
CSIS examined six years of satellite imagery of Kuh-e Kolang Gaz La, commonly known as Pickaxe Mountain, an underground complex about two kilometers south of Natanz and roughly 225 kilometers south of Tehran.
The analysis found more road activity at the site in 2026 than at any previous point in its history and what researchers described as a “clear surge in construction activity.”
Recent work included raising and hardening tunnel entrances, paving internal roads, reinforcing access areas and removing excavated soil, according to images taken in July and August.
The researchers said the activity indicated that work had shifted from excavation toward probable construction inside the complex, while reinforcement of its exterior continued.
CSIS outlined three possible purposes for Pickaxe Mountain: a centrifuge assembly facility, a uranium enrichment plant or a protected location for other nuclear-related work, including uranium metal conversion.
The report said publicly available evidence was insufficient to determine what Iran intended to place inside the complex. It could neither confirm nor disprove reports that Tehran had moved centrifuges or centrifuge components there.
Continuous construction, the absence of increased internal security and the lack of vehicles or equipment unrelated to building work suggested the site was “not yet capable of enrichment work,” if enrichment was its intended purpose, the analysts said.
CSIS also said the complex would be extremely difficult to destroy using conventional weapons because it is buried deep inside a granite mountain.
Open-source estimates place parts of the facility between 80 and 100 meters underground, but the report cautioned that satellite imagery could not reliably establish its depth or internal design.
The GBU-57 Massive Ordnance Penetrator, the heaviest conventional bunker-busting bomb in the US arsenal, may not be able to reach and destroy the complex, according to the analysis.
A military operation could instead seek to collapse the tunnel entrances, potentially degrading or temporarily disabling the facility without destroying it.
CSIS concluded that military strikes might delay work at the facility but would not offer a sustainable solution to concerns about Iran’s nuclear program, arguing that any lasting resolution would require a verifiable diplomatic agreement.
The IAEA has requested information about Pickaxe Mountain and access to the site, but Iran has not responded, the report said.
Iran began building the facility in 2020 after an aboveground centrifuge assembly workshop at Natanz was damaged in suspected Israeli sabotage. Iranian nuclear chief Ali Akbar Salehi said at the time that a replacement centrifuge assembly facility would be built underground near Natanz.
US President Donald Trump said on September 4 that Washington may strike Pickaxe Mountain “very soon,” reiterating that Iran would not be allowed to have a nuclear weapon.
The Pentagon has made preparations this year to test classified capabilities against deeply buried targets, CNN reported on Wednesday, citing federal contracting records and people familiar with the effort.
Days before the war began on February 28, the Defense Threat Reduction Agency approved an emergency $1.2 million contract to repair a specialized underground testing facility at White Sands Missile Range in New Mexico. The work was intended to prepare the site for a live-fire test against rapidly emerging threats, according to the records.
Three sources told CNN that the planned test was connected to the Iran war and efforts to develop a way to strike Iran’s deepest underground facilities, potentially by simulating attacks on specific nuclear sites.
Satellite imagery reviewed by CNN showed excavation and vehicle activity at the White Sands site beginning in mid-February and continuing into March. CNN said it could not independently verify whether the test occurred or determine its purpose. The Pentagon and the contractor did not provide comment.
The US military also maintains operational plans for striking Pickaxe Mountain, and the facility was included in a target package considered earlier this summer, a source familiar with the matter told CNN. The plan involved some of the largest bombs in the US arsenal, though it remained unclear whether they could penetrate deeply enough to destroy the facility.
Another source told CNN that Defense Department officials recently held a “planning sprint” on options for attacking deeply buried sites. The US Air Force is separately developing a next-generation penetrator to replace its existing bunker-busting bomb, with initial prototype work commissioned in September 2025.
The case has been sent to a Revolutionary Court, with some of the defendants accused of “leading the unrest” or “inciting war and killing,” charges that can carry severe penalties under Iranian law.
The document lists 75 prisoners as defendants in the case, while prosecutors in Isfahan have ordered at least 26 of them to stand trial.
The case was opened after unrest and a fire at Isfahan Central Prison, also known as Dastgerd, following an air strike near the prison in March. A military base and ammunition depot behind the prison were hit, while parts of the prison grounds and accommodation areas were also damaged.
Information accompanying the document said some prisoners were killed during the incident, and others died in the fire.
Human rights groups, citing witnesses and relatives of prisoners, have said the unrest began after missiles struck a military site behind the prison and projectiles also hit parts of the prison complex. Guards and prison officials left some posts after the explosions, and inmates came out of their wards fearing the facility could collapse, according to those accounts.
The groups said some prisoners then set fire to blankets, sheets and other materials in an effort to force authorities to open doors and allow them into safer areas. Smoke spread through enclosed corridors as the fires grew.
Human rights groups have also said security forces later entered the prison and used live ammunition, pellet rounds and tear gas against inmates. According to witness accounts cited by the groups, some prisoners were shot, while others died from burns or smoke inhalation during the unrest.
Serious charges brought
Prosecutors have brought charges including "inciting people to war and killing each other with the aim of disrupting national security," deliberate arson, destruction of public facilities and taking part in an illegal prison gathering that led to a riot during wartime, according to the document.
Other accusations include destroying surveillance cameras, windows and security doors, taking part in or assisting with property damage and setting fire to the prison infirmary.
Iran International identified 17 prisoners facing such accusations. The documents indicate that 18 prisoners could face death sentences.
Five prisoners executed in separate case
The referral to the Revolutionary Court comes after five protesters held at Dastgerd were executed over the past two months in a separate case known as the "Alikhani Square" case.
Five other people sentenced in that case are at risk of imminent execution.
The latest case comes amid a rise in executions and heavy prison sentences in Iran in recent weeks as tensions with the United States have intensified.
Concerns over prison conditions
Concerns over Dastgerd have also grown over treatment of inmates and health conditions.
Political prisoner Abdolrasoul Mortazavi said in an audio message from the prison in June that some people detained during the January protests had been tortured. He also reported beatings, harsh interrogations, restrictions on contact with families and limits on outdoor exercise.
Iran International has also received reports of worsening health conditions and a meningitis outbreak at the prison in recent weeks.
A source familiar with the situation told Iran International in August that several prisoners had died from infectious diseases. Information obtained by Iran International also indicated that meningitis had spread to most prison wards and that some inmates had been taken to Al-Zahra hospital in Isfahan.
Mahmoud Siadat told Iran's ILNA news agency that restrictions on exports of petrochemicals, steel, food and other goods had contributed to the decline, including limits imposed because of war damage and domestic demand.
Siadat said the greater concern was the speed at which other countries were moving into the market while Iranian trade was shrinking.
Rivals gain ground
"The more important problem is that during the same period in which we faced a decline in exports to Afghanistan, our competitors entered the Afghan market very seriously," Siadat said.
He said Uzbekistan's exports to Afghanistan had risen 42% this year, adding that the growth was rapidly reducing Iran's share of the Afghan market. He also pointed to what he described as a multibillion-dollar Saudi gas extraction agreement near Iran's border.
Saudi Arabia-based Delta Energy International signed an agreement with Afghanistan's Ministry of Mines and Petroleum this week to explore and extract oil and gas in the Kushk-Tirpul basin in the western provinces of Herat and Badghis.
Afghan authorities put the initial investment at $200 million, while Delta has said a wider energy program could involve tens of billions of dollars in potential investment if exploration and feasibility studies support further development.
The decline comes amid a broader contraction in Iran's foreign trade since the war began. An Iranian trade official has said non-oil exports and imports fell by about 30% in the first four months of the current fiscal year, while customs data from China and Turkey showed steep declines in trade with Iran. Indian exports to Iran also fell sharply, although India's imports from Iran rose on higher purchases of Iranian crude oil and liquefied petroleum gas.
Trucks wait for up to 15 days
Siadat said Iran was also hurting its position in Afghanistan through long delays at its own borders, with hundreds of trucks waiting to cross at Milak and Dogharoun.
He said some trucks were being held for between 12 and 15 days before leaving Iran, while traffic moved much more smoothly on the Afghan side.
"There is no logic in our trucks being held for 13, 14 and sometimes 15 days at the border with Afghanistan," he said. "Long stops at the border cause an unusual increase in transport costs and freight rates and reduce our competitiveness in the Afghan market."
Siadat broadened his criticism beyond border management, saying the problem reflected wider weaknesses in Iran's state structure and fragmented decision-making.
"Many of the organizations that are not even directly under the government's supervision play a fundamental role in creating this problem," he said, adding that regulatory and military bodies needed to reach a common position.
He also criticized the limited role of businesses in policymaking. "The private sector in Iran is, in many cases, largely a ceremonial presence in decision-making," he said. "It only hears promises but sees no action."
US pressure adds to wider trade strain
Siadat said, however, that sanctions were making Iranian goods more expensive in export markets, adding another layer of pressure on businesses already dealing with transport restrictions.
The United States has intensified economic pressure on Iran through an oil export blockade and expanded secondary sanctions aimed at restricting Tehran's access to dollars, foreign financing and international trade channels. Iran's total trade has fallen by between 25% and 35%, according to President Masoud Pezeshkian.
Washington has continued to add measures. The US Treasury on Tuesday imposed a new round of Iran-related sanctions targeting the country's aviation sector and companies and intermediaries in several countries, part of the Trump administration's wider economic pressure campaign.
Siadat said Afghanistan had become more important because problems at Iran's southern ports and other trade routes had cut or reduced transit flows.
"Afghanistan's border is currently one of the few borders through which we can work," he said, warning that delays on the Iranian side were putting one of the country's remaining export outlets at risk.
“It is quite wrong for the IRGC to be threatening journalists simply for doing their job,” Ciccone, Chair of Parliament’s Joint Committee on Intelligence and Security, said. “Journalists are entitled to report on what is occurring anywhere around the world, particularly the events in Iran.”
He said journalists must be able to work “without harassment or intimidation, or violence for that matter,” adding that Iranians had a right to independent reporting about events inside the country.
“The Iranian people are looking to the rest of the world to understand what is happening,” Ciccone told Iran International. “They have a right to independent reporting, and journalists must be protected while carrying out that work.”
He said the threats also affected Iranian journalists and government opponents living abroad, including members of the diaspora in Australia.
He described such threats as part of a broader pattern of intimidation by the IRGC and said governments should respond collectively.
“It’s no surprise that these threats are coming from the IRGC,” Ciccone said. “But intimidation cannot be allowed to silence journalists or communities overseas.”
Ciccone pointed to steps already taken by Australia and said Canberra should continue working with international partners to hold Iranian authorities accountable.
“We also have to stand by the Iranian people,” he said. “The Iranian people are looking to the rest of the world for their support, and I can say that many people in Australia are with them 100%.”
He said Australia, Canada, Germany and other countries should stand with Iranians and condemn threats against journalists. He also backed diplomatic expulsions, sanctions against those linked to the IRGC and further action against the organization.
A senior official with Iran’s armed forces said in late August that journalists working for Persian-language media abroad could be placed on a list of military targets.
“Media outlets such as Iran International, BBC Persian and Radio Farda are directly connected to Mossad, the US Central Intelligence Agency and other foreign intelligence services and receive support from them,” said Abolfazl Shekarchi, a brigadier general and senior spokesman for Iran’s armed forces.
After his remarks, Canada also said its security and intelligence agencies are using a full range of tools to counter foreign interference and transnational repression.
In a response to Iran International, Public Safety Canada said authorities continuously monitor such threat s and can respond through investigations, criminal charges and disruption activities.
But the fighting is also showing why a weakened axis can remain dangerous: it does not have to win territory to impose costs on Iran’s adversaries.
Yemen’s Houthis dramatically escalated their attacks on Saudi Arabia on Tuesday, striking four southern cities with missiles and drones. The group targeted a Saudi airbase in Khamis Mushait and Saudi Aramco assets in Abha, Najran and Jazan, setting oil installations ablaze. Saudi authorities said 73 people were wounded, including women and children.
The attacks also threatened to widen the war’s economic impact beyond the Strait of Hormuz, where the US-Iran conflict has already disrupted energy flows. Brent crude briefly touched $99.46 a barrel on Tuesday, its highest level since July 24.
“They’re not really fighting five separate wars, they’re just using five instruments of the same coercive strategy,” Fatima Abo Alasrar, a researcher and author on Yemen and Iran and founder of The Ideology Machine, told Iran International.
The timing, Alasrar said, matters.
Iran is exerting pressure around the Strait of Hormuz while the Houthis can create another pressure point around Bab al-Mandab, forcing Iran’s adversaries to contend with threats near two of the world’s most important maritime chokepoints.
“The lesson that the Houthis appear to have learned is that escalation produces leverage,” she said, even without territorial gains.
That leaves Saudi Arabia with a difficult choice: escalate in an effort to substantially weaken the Houthis and risk a wider war or seek a political exit that could reinforce the belief in both Sanaa and Tehran that military pressure can ultimately produce concessions.
Houthis called Saudi Arabia’s bluff
Mohammed al-Basha, a Yemeni-American geopolitical analyst and risk adviser who heads the Washington DC-based Basha Report, said the Houthis helped bring about the renewed war by assuming Saudi Arabia and Yemen’s internationally recognized government would avoid a return to full-scale fighting.
“The Houthis were hoping to call a bluff — a Saudi and a government bluff,” al-Basha told Iran International.
Asked whether they miscalculated, he replied: “Of course, of course.”
Yet al-Basha said the Iran war has also reinforced the Houthis’ belief in the value of escalation.
“They feel that the best way for you to get what you want is to use force,” he said.
The confrontation follows an earlier dispute over an Iranian aircraft carrying a Houthi delegation back from Tehran following the funeral of Supreme Leader Ali Khamenei.
Analysts told Iran International at the time that the flight may have been an opening move in an effort to establish an air bridge into Houthi-controlled Yemen and rebuild the group’s strategic capabilities.
“The alliance is no longer secretive or covert, it’s very public,” al-Basha said of the Iran-Houthi relationship.
Can battlefield gains change the equation?
Forces loyal to Yemen’s internationally recognized government have now launched counterattacks across several fronts, with officials openly declaring their intention to eventually recapture Sanaa.
But al-Basha cautioned against assuming the Houthis are close to defeat. He said losing strategically important territory, rather than simply patches of ground, could eventually push them toward negotiations.
One place to watch is Hodeidah, whose port al-Basha described as “the lung that the Houthis breathe from.” The group’s position around Hodeidah, Bab al-Mandab and the Red Sea is central to its ability to threaten maritime traffic.
Alasrar, however, said territorial losses do not necessarily eliminate Houthi leverage.
“They can lose ground and still increase their regional leverage,” she said.
The Houthis have threatened further attacks against Saudi economic and military infrastructure, raising the prospect of greater disruption around Bab al-Mandab while the Iran conflict continues to put pressure on Hormuz
A ‘win-win’ for Tehran?
Danny Citrinowicz of Israel’s Institute for National Security Studies sees that predicament as advantageous for Iran.
“For them it’s amazing. So it’s a win-win for them,” Citrinowicz told Iran International.
If Saudi Arabia backs down, he argues, Iran gains room to strengthen the Houthis. If Riyadh keeps fighting, instability around Bab al-Mandab creates another source of economic pressure while Iran contests Hormuz.
“It definitely worked in the Iranian favor,” he said. “The Iranians are learning from that, unfortunately.”
But it leaves Saudi Arabia with two costly options. Citrinowicz said the Houthis have “crossed the Rubicon” and are unlikely simply to retreat. As Saudi-backed forces approach areas the group considers critical, he expects Houthi attacks against the kingdom to intensify.
A moment of truth for the Mecca Defence Alliance
The escalation is also posing an early test for the Mecca Defence Alliance, the collective defense pact signed by Saudi Arabia, Turkey and Pakistan on August 7.
The agreement stipulates that an armed attack against any one of the three countries is to be regarded as an attack against all three.
Yet neither Turkey nor Pakistan has so far entered the fighting militarily on Saudi Arabia’s behalf.
Citrinowicz calls it “a moment of truth” for the alliance, with neither country so far entering the fighting militarily.
Will Washington hold Iran responsible?
The United States is now explicitly pointing toward Tehran.
“The Houthis in many ways are agents and proxies of the Iranians. I think behind some of this is clearly the Iranian hand,” US Secretary of State Marco Rubio told reporters when asked about the attacks on Saudi Arabia.
Rubio said Washington has a strong defensive military relationship with Riyadh and is closely watching developments.
His comments revive a warning President Donald Trump issued on July 23.
Trump said then that Washington would hold Iran responsible if the Houthis resumed attacks, describing the group as a “Surrogate and/or Proxy of Iran” and warning of “major military punishment” against Iran and the Houthis.
The Houthis have now resumed major attacks against Saudi Arabia. Rubio has publicly pointed to an Iranian hand, but Trump has yet to publicly repeat the threat he made in July.
That leaves a consequential question as the conflict widens: if Washington considers the Houthis an Iranian proxy, how far is it prepared to go in holding Tehran responsible for what they do?
The coming days and weeks are likely to bring advances and retreats on both sides, with territory changing hands and apparent victories proving temporary. The battlefield remains highly fluid, and both sides appear determined to keep fighting, making it too early to draw sweeping conclusions from any single development.
But even without a clear Houthi victory, Iran may stand to gain. As long as the fighting forces Saudi Arabia to expend resources, keeps pressure on Bab al-Mandab and stretches the attention of Tehran’s adversaries, the Houthis can continue to provide Iran with leverage even while under pressure themselves.
The conflict has a long way to go for now and consequences reverberate from Yemen across an already destabilized region.
