Iranian Foreign Minister Mohammad Javad Zarif has called on Britain to accelerate efforts meant to release an Iranian oil tanker held in the British overseas territory of Gibraltar since earlier this month.

“The UK government must immediately adopt required measures to end the illegal seizure of the Iranian oil tanker,” said Zarif in a phone conversation with his British counterpart Jeremy Hunt on Saturday.

The top Iranian diplomat said that Britain was supposed to continue to defy extra-territorial sanctions imposed by the United States on Iran as a matter of conformity with other members of European Union.

The phone conversation between Iranian and British foreign ministers came 10 days after British naval forces seized the Grace 1 supertanker off the coast of Gibraltar as it was sailing to the east Mediterranean region. Authorities in the British controlled territory said at the time that they had stopped the ship suspecting it was carrying oil to Syria, a destination banned under current EU regulations.

Zarif told Hunt, however, that the seizure of the Grace 1 had been inspired by US sanctions on Iran, which began last year when Washington unilaterally withdraw from an international agreement on Tehran’s nuclear program.

He said that Iran would continue to exhaust all avenues to export its oil despite the existing sanctions.

“The Islamic Republic of Iran will continue its oil export under any circumstances,” said Zarif, according to an excerpt of the phone call with Hunt covered on the website of the Iranian Foreign Ministry.

For his part, Hunt expressed hope that legal and judicial examinations in Gibraltar would lead to the immediate release of the Grace 1 and its oil cargo.

The British foreign secretary insisted that Iran was entitled to its rights to export crude despite the US sanctions, saying, however, that he was worried about escalated tensions in the Persian Gulf region where a series of military incidents over the past weeks have increases concerns about a potential conflict between Iran and the US.