The US requested that Gibraltar halt the release of a detained Iranian tanker on Thursday and turn the vessel over to US officials.“The US Department of Justice has applied to seize the Grace 1 on a number of allegations which are now being considered,” the government of British overseas territory announced in a statement released Thursday.The Gibraltar Chronicle reports that the last-minute request, from the US department of justice, has prompted the British territory’s Supreme Court to hold off on an official decision on the tanker until later Thursday. Further details about the US’s allegations were not immediately available. The captain of the vessel and three officers have been formally released, a Gibraltar government spokesperson said.Several tanker disputesOn July 4, commandos for the British Royal Navy led an operation to seize the tanker, Grace 1, on suspicion that it was violating EU sanctions on shipping oil to Syria. The seizure of the supertanker, which was carrying 2.1 million barrels of Iranian oil, also heightened international tensions in the Persian Gulf.Most of the crew were Indian and Pakistani nationals. Iranian officials demanded the immediate release of the tanker on July 5. The Foreign Ministry described the UK government’s capturing of the ship as “unacceptable” in a statement.Also read: Iran Seizes ‘Foreign’ Vessel in Persian GulfLater in July, Iran seized two vessels in the Strait of Hormuz, one sailing under a British flag and the other bearing the banner of Liberia. “These seizures are unacceptable,” British Foreign Secretary Jeremy Hunt said, before warning of “serious consequences” if the issue was not resolved quickly. Iran is still holding the ship.USA’s request on Thursday is a potential hindrance to a swapping of the vessels, though no such agreement had been formally reached. Had USA not intervened, Gibraltar Chief Justice Anthony Dudley said, “the ship would have sailed.”This article was originally published on Deutsche Welle.