The vessel was hit near Hengam Island, south of Qeshm Island, Qeshm Governor Hossein Amir-Teymouri told state-run IRNA. Ten crew members were aboard, he added.
One crew member, Jamshid Rajabi, was killed and four others injured. Iranian authorities have not identified the projectile or said who was responsible.
UK Maritime Trade Operations separately said a vessel transiting the Strait of Hormuz had been struck by an unknown projectile. A fire broke out and local authorities assisted with the crew’s evacuation, UKMTO added.
Neither UKMTO nor Iranian authorities have confirmed that the reports concerned the same vessel.
Iran rules out reopening Hormuz
The attack came a day before a regional meeting in Oman on a proposed maritime route through the Strait of Hormuz.
Iran will brief participating countries on an agreement with Oman and present maps of the proposed corridor, Foreign Minister Abbas Araghchi told Al-Araby Al-Jadeed.
“The agreement with the Sultanate of Oman does not in any way mean the reopening of the Strait of Hormuz,” Araghchi said.
Tehran would agree to reopen the waterway only if the United States returned to its commitments under the Islamabad memorandum, Araghchi added.
The strait has become a major front in the conflict, with the United States and Iran targeting vessels and disputing control over maritime traffic.
Meanwhile, hardline Iranian newspaper Kayhan called for a sharp expansion of retaliation against attacks on Iranian oil tankers, proposing that Tehran target multiple vessels for every Iranian tanker hit.
“The Islamic Republic of Iran must officially announce that, from now on, if one Iranian tanker is attacked, it will target all tankers in the Persian Gulf and the Gulf of Oman,” Kayhan wrote.
The newspaper, published under the supervision of supreme leader’s representative, argued that disabling large numbers of tankers could cause a global supply shortage and drive oil prices sharply higher.
Saudi-Houthi confrontation widens
Shipping risks have also increased on the other side of the Arabian Peninsula, where Yemen’s Iran-backed Houthis said they targeted Saudi military facilities with ballistic missiles and drones.
Houthi military spokesperson Yahya Saree said the group struck weapons depots and command facilities at a Saudi base in the southern Sharurah region in response to Saudi military operations in Yemen.
Saudi authorities did not immediately confirm the attack.
Iranian President Masoud Pezeshkian sought to distance Tehran from the confrontation.
“We are not at war with Saudi Arabia,” Pezeshkian said. “The Houthis have their own issues.”
His comments followed a drone strike on Saudi Arabia’s East-West oil pipeline, which Riyadh temporarily shut down. The route provides an alternative to shipping oil through the Strait of Hormuz.
Iraqi authorities said drones used in the pipeline strike were launched from Iraqi territory. Iraq subsequently seized 15 drone-launch platforms and pledged to prevent its territory from being used for attacks on neighboring countries, Al Arabiya reported.
The Houthi operations have raised the prospect of simultaneous disruption around the Strait of Hormuz and Bab el-Mandeb, two of the world's most important maritime energy routes.
Lawmakers raise nuclear withdrawal
Iranian politicians have meanwhile raised the possibility of withdrawing from the Nuclear Non-Proliferation Treaty following a resolution by the International Atomic Energy Agency’s Board of Governors.
Leaving the treaty and reconsidering Iran’s nuclear doctrine were “entirely attainable and readily achievable,” parliament presiding board spokesperson Abbas Goudarzi said.
Such measures would “put the United States and its lackeys in their place,” Goudarzi added.
However, two members of parliament’s National Security and Foreign Policy Committee said no legislation to withdraw from the NPT had been submitted to the panel.
Their accounts contradicted lawmaker Hosseinali Hajideligani, who earlier said several lawmakers had signed an expedited bill seeking withdrawal. Hajideligani has also called for tests needed to develop a nuclear weapon, arguing that Iran requires “atomic deterrence.”
A Foreign Ministry official separately said Iran had denied IAEA inspectors access to some nuclear sites following attacks by the United States and Israel.
Diplomacy continues at BRICS summit
Diplomatic contacts continued alongside the military and nuclear disputes, with Pezeshkian meeting Abu Dhabi Crown Prince Sheikh Khaled bin Mohamed bin Zayed on the sidelines of the BRICS summit.
UAE presidential adviser Anwar Gargash said the meeting reflected Abu Dhabi’s approach of combining deterrence with diplomacy.
“Neither can function properly without the other,” Gargash said. “Deterrence strengthens the credibility of diplomacy, while diplomacy succeeds when it begins from a position of parity and capability.”
Gargash also praised Pezeshkian’s approach during the crisis, describing his positions as “balanced and rational.”
Araghchi separately released images of conversations with the foreign ministers of Russia, China, Egypt, Indonesia and Kazakhstan at the summit, without providing details of what was discussed.
Monday’s talks in Oman will take place with the Strait of Hormuz still closed and no responsibility established for Sunday’s deadly strike, leaving the proposed maritime corridor facing an immediate test of whether ships can use it safely.