An Iranian tanker detained in Gibraltar last month is again underway after a court in the British territory rejected a request from Washington to formally seize the vessel for violating international sanctions.
The Grace 1, now renamed Adrian Darya 1, was intercepted by British Royal Marines on July 4, allegedly because it was carrying its cargo of 2.1 million barrels of light crude oil to Syria.
Iran has denied the ship was headed to Syria.
As of Monday afternoon in the Mediterranean, MarineTraffic, a site that tracks shipping by monitoring vessels' onboard beacons, showed the vessel steaming slowly on an easterly course.
As the tanker departed, Iran warned the U.S. not to stop the ship as it heads toward its next stop, reportedly at the Greek port of Kalamata.
"Such an action ... would endanger shipping safety in open seas," Abbas Mousavi, a spokesman for Iran's foreign ministry, told reporters. "We have issued a warning through official channels, especially the Swiss Embassy."
On Thursday, a court in Gibraltar lifted a detention order, concluding that Iran's pledge that the cargo wouldn't be shipped to Syria satisfied the conditions of European Union sanctions.
However, a U.S. federal court quickly issued a warrant for the vessel and its cargo to be impounded for violating U.S. sanctions. The court in the British overseas territory said Sunday that it was bound by EU, not U.S., law and ordered the ship to be released.
Two weeks after Grace 1 was detained, Iran retaliated by seizing a U.K.-flagged ship, the Stena Impero, which is still being held, reportedly at Bandar Abbas.
It wasn't clear whether the release of the Iranian ship would elicit a quid pro quo for the Stena Impero, but Mousavi, the foreign ministry spokesman, said Tehran had made "no commitment" in exchange for the Grace 1.