TEHRAN - Iran has called on Britain to release its seized oil tanker and warned foreign powers to “leave the region because Iran and other regional countries are capable of securing the regional security”.

The Royal Marines seized the tanker last week on suspicion it was breaking European sanctions by taking oil to Syria.

Iran’s foreign ministry spokesman, Abbas Mousavi, told the IRNA news agency: “This is a dangerous game and has consequences ... The legal pretexts for the capture are not valid ... The release of the tanker is in all countries’ interests.”

Iran has said it will take reciprocal measures if its tanker is not released.

Britain said on Thursday that three Iranian vessels tried to block the British-owned commercial vessel British Heritage from passing through the strait of Hormuz, which controls the flow of Middle East oil to the rest of the world, but backed off when confronted by a Royal Navy warship. Iran has denied the allegations.

Tensions between Iran and the west continue to rise, a week after Britain seized the tanker, with Mousavi accusing the UK of taking the action under US pressure.

“Such illegal measures could increase tensions in the Persian Gulf,” he told IRNA. The captain and chief officer of the ship were arrested in Gibraltar on Thursday, a week after the episode.

Shia-led Iran and its US-backed Sunni Gulf Arab rivals have been locked in proxy battles for dominance in the Middle East, from Syria to Yemen.

The UK is among the European supporters of the 2015 Iranian nuclear deal, from which Donald Trump withdrew the US last year, reimposing toughened sanctions on Tehran.

When imposing the sanctions in May, the US ordered other countries and companies to halt imports of Iranian oil or face being excluded from the global financial system.

In retaliation, Iran has decreased its commitments to the nuclear pact, in defiance of a warning by European countries.(FA)