TEHRAN — Iran has seized a Marshall Islands-flagged oil tanker in the Gulf of Oman, state media reports. Armed men wearing masks have reportedly boarded the vessel St Nikolas, close to the Omani port of Sohar, and ordered it to sail to an Iranian port. It is unclear why the tanker has been targeted. The St Nikolas was in transit between the Iraqi port of Basra and its intended destination in Turkey. UK Maritime Trade Operations said on Thursday it had received a report that four to five "unauthorized persons", reportedly wearing "military style black uniforms with black masks", had boarded the ship at 03:30 GMT. They added that communications with the vessel had been lost and that the authorities were investigating. Iranian state media quoted the army as describing the vessel as being American The company that manages it, Empire Navigation, said it was loaded with 145,000 tons of crude oil and was carrying 18 Filipinos and one Greek person as crew. The St Nikolas was seized in April by the US under its previous name, the Suez Rajan, as part of sanctions enforcement against Iran. Suez Rajan Limited, which formerly chartered the boat, later pleaded guilty to conspiring to violate sanctions by covertly selling and transporting oil abroad on behalf of Iran. This latest act appears to be separate from attacks carried out by Houthi rebels from Yemen in the Red Sea. Thursday"s incident was in a different area to the Houthis" area of operations — where they have been attacking any ships they suspect of being linked to Israel in retaliation for the country"s actions in Gaza. The US and UK have hinted they could take military action against Yemen"s Houthi rebels following the largest attack yet. Carrier-based jets and warships shot down 21 drones and missiles launched by the Iran-backed group on Tuesday night. The UN Security Council passed a resolution on Wednesday demanding an immediate end to the Houthi attacks. — BBC