IRAN’S navy captured an oil tanker in the Gulf of Oman on Thursday that only months earlier had seen its cargo of Iranian oil seized by the United States.

The St Nikolas, previously known as the Suez Rajan, was involved in a dispute beginning in 2021 that ultimately saw the US Justice Department seize the one million barrels of Iranian crude oil on it.

The Iranian navy’s “seizure of the oil tanker does not constitute hijacking; rather, it is a lawful undertaking sanctioned by a court order and corresponds to the theft of Iran’s very own oil,” Iran’s mission to the United Nations said in a statement. 

“Adhering to the established legal procedures is the most prudent approach for the resolution of this matter.”

The British military’s United Kingdom Maritime Trade Operations, which provides warnings to sailors in the Middle East, said Thursday’s seizure began early in the morning in the waters between Oman and Iran in an area transited by ships coming in and out of the Strait of Hormuz, the narrow mouth of the Persian Gulf through which a fifth of all traded oil passes.

The private security firm Ambrey said that “four to five armed persons” boarded the ship, which it identified as the oil tanker St Nikolas. It said the men covered the surveillance cameras as they boarded.

The tanker had been off the city of Basra, Iraq, loading crude oil bound for Aliaga, Turkey, for the Turkish refinery firm Tupras. 

US State Department spokesperson Vedant Patel condemned Iran’s seizure of the vessel.

“The Iranian government must immediately release the ship and its crew,” Mr Patel said. “This unlawful seizure of a commercial vessel is just the latest behaviour by Iran — or enabled by Iran — aimed at disrupting international commerce.

The US and its allies have been seizing Iranian oil cargoes since 2019 to enforce sanctions over the Islamic Republic’s nuclear programme.