Israel’s Shin Bet security agency says it arrested four Arab-Israelis in July on charges of smuggling Iranian-made explosive devices into the country and ties to Hezbollah.

According to Shin Bet, three individuals from the northern Arab town of Kafr Qasim were arrested on suspicion of smuggling "a substantial quantity of high-quality weapons" into Israel. The agency added that, during their arrest, they seized two Iranian-made explosive devices along with other weapons.

In a separate raid in the central city of Lod, security forces detained another Israeli who was allegedly planning to use a similar explosive device for a criminal-related bombing.

“The Shin Bet investigation revealed that Hezbollah worked to recruit and operate an infrastructure of smugglers in Israel for the purpose of distributing unusual illegal weapons to various parties, including criminal elements,” the agency said in a statement.

The Shin Bet identified the suspects as Jalal Khursa, 28, Ahmed Issa, 30, and Muhammed Issa, 39, from Kafr Qasim, and Nuh Assam, 30, from Lod. They were indicted Wednesday on various weapons offenses, making the agency publicize details of the investigation.

“This affair once again illustrates the efforts of terror elements from Hezbollah and Iran to exploit the Arab citizens of Israel for [terror] activities against the state,” a senior Shin Bet official said, adding, “It also emerged in the investigation that the line between [terror] and criminal [activity] is extremely thin.”

Hezbollah has been accused in the past of being involved in weapons and drug smuggling attempts. Most illegal guns in Israel and the West Bank are thought to have been smuggled via Jordan, with far fewer attempts from Lebanon. In late July, the military foiled a weapons smuggling attempt from Jordan.