Madrid: The United States moved on Thursday to halt the release of an Iranian supertanker detained in Gibraltar for breaching international sanctions on oil shipments, thwarting efforts by authorities in London and the British overseas territory to defuse tensions with Tehran. The Gibraltar government confirmed earlier media reports that the U.S. Justice Department seeks to extend the detention of the oil tanker Grace 1, prompting the Supreme Court in the territory to adjourn a scheduled decision on whether to release the ship until later in the day. "The US Department of Justice has applied to seize the Grace 1 on a number of allegations, which are now being considered," the Gibraltar government said in a statement, adding the matter would be reviewed by the court at 4 p.m. (local time).

The Justice Department did not immediately respond to a request for comment. Britain's Foreign Office said in a statement that the "investigations conducted around the Grace 1 are a matter for the government of Gibraltar" and that it couldn't comment further. Prime Minister Boris Johnson's Downing Street office said Iran was discussed during the UK leader's meeting with President Donald Trump's national security adviser John Bolton earlier in the week, though no details were released on the talks. While there was no immediate reaction from Tehran, the US move likely will further stir tensions in the Persian Gulf. The Grace 1, carrying 2.1 million barrels of Iranian crude oil, was seized last month in a British Royal Navy operation off Gibraltar. The vessel was suspected of violating European Union sanctions on oil shipments to Syria, and its seizure deepened international tensions in the Persian Gulf. Iran called the seizure by Gibraltar an "act of piracy."