The British overseas territory of Gibraltar turned back U.S. objections on Thursday and released the Iranian supertanker Grace 1 from detention, after receiving assurances from Tehran that it would not send its crude oil cargo to Syria.
"There are no longer reasonable grounds to suspect that the detention of the vessel is required," chief minister Fabian Picardo said in a statement.
Hours earlier, the U.S. signaled it wanted to block the release of the ship, which had been seized by Britain July 4. That delayed the ruling, but Chief Justice Anthony Dudley said he had not received a written request from the U.S.
The U.S. could, however, could still seek to detain the ship as long as it remains in Gibraltar's waters. It was unclear how soon the ship might sail away.
The Grace 1 had been carrying 2.1 million barrels of Iranian oil when Gibraltar police and British special forces seized it, one of a string of weeks of provocations involving Western nations and Tehran, most of which have occurred in the Persian Gulf or at other spots in the Mideast. The tanker was believed to be transporting the oil to Syria in violation of separate European Union and U.S. sanctions.
After seizure of the Grace 1, Tehran retaliated by taking control of a British tanker, the Stena Impero, on July 19 in the strategic Strait of Hormuz -- the shipping lane for about a fifth of the world's crude -- for breaking "international maritime rules." Iran still holds the Stena Impero.
Iran had repeatedly called for the release of the Grace 1, saying it had been international waters and was not headed to Syria.
Tehran condemned the last-day U.S. efforts to block the release of the ship.
Iranian Foreign Minister Mohammad Javad Zarif said on Twitter, "Having failed to accomplish its objectives through its #EconomicTerrorism -- including depriving cancer patients of medicine -- the U.S. attempted to abuse the legal system to steal our property on the high seas. This piracy attempt is indicative of Trump admin's contempt for the law."
The dispute over the tanker is part of the ongoing confrontation between U.S. President Donald Trump and the Iranian regime over its nuclear weapons program after the U.S. leader withdrew the U.S. from the 2015 international agreement aimed at restraining Tehran's nuclear program in exchange for lifting crippling economic sanctions against Iran.
Trump subsequently reimposed U.S. sanctions, hobbling Iran's economy, in a so-far unsuccessful effort to force Iran to renegotiate the terms of the nuclear deal.