The United States applied on Thursday for Gibraltar to keep in detention an Iranian oil tanker at the center of a stand-off between Tehran and London, the public prosecutor said.

The announcement by attorney Joseph Triay delayed a court decision on whether to extend the detention of Grace 1, which is suspected of smuggling oil to Syria and has been held since July 4.

Triay did not detail in court the basis for the US request other than as "mutual legal assistance".

Chief Justice Anthony Dudley made clear that were it not for the US move, "the ship would have sailed" from the overseas British territory.

The Gibraltar Supreme Court decision on the fate of the ship has been adjourned until after four pm (14:00 GMT).

The captain and three officers from Grace 1, had their bail lifted and were formally released, a Gibraltar government spokesman said.

The supertanker, carrying 2.1 million barrels of Iranian oil, was seized by Gibraltar police and British special forces, provoking a diplomatic crisis. It was suspected of carrying oil to war-torn Syria in violation of EU sanctions.

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