More than 2 million barrels of crude oil on Adrian Darya sold to unknown buyer who will decide vessel’s destination.

Iran has sold 2.1 million barrels of crude oil on board an Iranian tanker that was detained by British Royal Marines in Gibraltar last month, and the vessel’s new owner will decide on its next destination.

The announcement on Monday by government spokesman Ali Rabiei is the latest twist in the saga of the Adrian Darya 1, which was known as the Grace 1 when authorities seized it off Gibraltar on July 4 on suspicion of breaking European Union sanctions on Syria.

The seizure of the ship, and Iran’s subsequent seizure of a British-flagged oil tanker in the Strait of Hormuz, came amid heightened tensions between the United States and Iran over the collapse of Tehran’s nuclear deal with world powers.

Speaking to journalists in the capital, Tehran, Rabiei declined to name the oil’s buyer or terms for the sale. At current market rates, the crude oil on board the Adrian Darya 1 would be worth about $130m.

“The Islamic Republic of Iran has sold the oil of this ship and now the owner and purchaser of this oil will decide the destination of the cargo,” Rabiei said, as quoted by state media.

“We believe and are sure that the owner of the ship will take it to where it is supposed to go and we are not informed of its final destination,” he added.

The vessel set sail from the British territory of Gibraltar on August 18, after more than six weeks in detention, despite a last-minute request by the US to stop the release.

A US court had issued a warrant for the seizure of the vessel and its cargo on the grounds that it had links to Iran’s Islamic Revolutionary Guard Corps (IRGC), which Washington has designated a “terrorist” organisation. But Gibraltar’s government rejected the request.

Rabiei said the world is “witnessing the wrong policy by the US in monitoring and intervention in others’ internal affairs”.

The tanker is currently in the Mediterranean Sea, south of mainland Greece and west of the island of Crete, Refinitiv Eikon shipping data showed.

Al Jazeera’s Assed Baig, reporting from Tehran, said: “Because Iran has been very secretive about who has bought this oil and where the vessel is heading, there are many possible routes.”

“It could go down the Suez Canal, it could go back via Gibraltar and around Africa and back to Iran,” he said. “It could go to the Black Sea, through the Caspian Sea and dock in the north of Iran, so right now we still don’t know where it’s headed.”

Separately on Monday, Iran announced that it had deployed a naval destroyer with cruise missiles to help secure Iranian ships.

Iran’s state-run Press TV said the newly deployed destroyer was equipped with long-range cruise missile systems and had been dispatched to the Gulf of Aden to provide security for Iranian ships travelling through the region.