Tehran has accused Ukraine of attacking an Iranian commercial vessel in the Caspian Sea, resulting in an explosion that killed one sailor and injured another.

Iran’s Ministry of Foreign Affairs summoned Ukraine’s chargé d’affaires in Tehran to protest what it described as a “hostile and criminal” attack that occurred on Saturday, according to state news agency IRNA.

The ministry asserted that the attack had been acknowledged by the Ukrainian leadership and characterized it as evidence of Kyiv’s continued “irrational and hostile approach” towards Iran. Iran warned it would defend its national interests and stated the incident constituted a violation of Article 2(4) of the United Nations Charter, potentially escalating the Russia-Ukraine war.

Iranian Foreign Minister Abbas Araghchi discussed the incident in a phone call with the European Union’s High Representative for Foreign Affairs Kaja Kallas. Araghchi strongly condemned the attack and called for a firm response from the United Nations Security Council, the European Union, and the international community, demanding accountability for the perpetrators and their supporters.

"The Iranians are not really happy with [the attack], while they’re also dealing with a US blockade on the southern coast," said Al Jazeera’s Tohid Asadi, reporting from Tehran. He added that attacks on Iran’s northern coast are "putting extra pressure" on Iran’s maritime trade.

In its condemnation, Iran’s Foreign Ministry reiterated that Tehran has not intervened in the Russia-Ukraine conflict. The incident follows Ukrainian President Volodymyr Zelenskyy’s announcement of “very strong results” from long-range strikes in the Caspian Sea, targeting “vessels used in military cargo shipments involving Iran, as well as a warship.” Zelenskyy did not specify the commercial vessel mentioned by Tehran.

Zelenskyy also alleged that Russia had provided Iran with satellite imagery of Gulf states and U.S. military sites, with surveillance occurring on July 19 and 20 over airbases in Bahrain, Jordan, and Kuwait.

Relations between Iran and Ukraine have been strained since 2022, when Iran supplied Russia with Shahed drones, which Moscow has extensively used against Ukrainian cities. Ukraine claims to have intercepted over 44,000 Iranian-designed drones since the conflict began.