The source said drones were likely used and that there were no reports of casualties.

There was no immediate comment by Iran, which has rejected accusations it was behind similar incidents in the past few years.

The attack came during tension between Iran and the West over Tehran’s nuclear activity and its supply of arms — including long-range “suicide drones” — for Russia’s war in Ukraine, as well as months of anti-government demonstrations at home.

British maritime security company Ambrey Intelligence said unmanned aerial systems had attacked two tankers and one bulk carrier in the Arabian Sea and assessed that Tehran had mounted the attack. Two of the merchant vessels were Israeli-owned, it said, and one was Emirati.

Iran has blamed Israel for a Jan. 29 drone attack on a military site in the central city of Isfahan, vowing revenge for what appeared to be the latest episode in a long-running covert war.

Several nuclear sites are located in Isfahan province, including Natanz, the centerpiece of Iran’s uranium enrichment program, which Iran accuses Israel of sabotaging in 2021. There have been many explosions and fires around Iranian military, nuclear and industrial sites in recent years.

Israel’s Defense Minister Yoav Gallant said on Friday that Iran was expanding its advanced weapons proliferation beyond the region despite an embargo, including talks to sell drones and precision-guided munitions to 50 countries.