An Iranian-flagged tanker seized by Greece in April, part of whose cargo was confiscated by the US, was released and towed to the port of Piraeus on Saturday, the Greek coastguard said.
The Lana was anchored off the Greek island of Evia for more than two months as a diplomatic impasse strained Athens' relations with Tehran.
“It left Karystos (town) at 06.30am [0330 GMT] and is expected to reach Piraeus around 10pm,” one official said.
In April, Greece impounded the Lana, with 19 Russian crew members on board, and its oil cargo off Evia following US sanctions.
That decision was overturned on June 10 because of complications over ownership, but until last week the ship was detained by another company for towing services debts.
The Lana, which has engine problems, was released after the debt was paid, legal sources told Reuters.
Part of the ship's Iranian oil cargo had been transferred to another ship, Ice Energy, which was hired by the US and is moored off Piraeus port.
Following an appeal by an Iranian company on June 7, a Greek judicial panel overturned the court order that had allowed the confiscation of the cargo on behalf of the US, clearing the way for Lana to retrieve it.
It was not immediately clear if it would do so, or if the US or Greek governments would challenge the latest ruling.
The removal of oil from the Lana prompted Iran last month to seize two Greek tankers in the Arabian Gulf and sail them to Iran after Tehran warned of “punitive action” against Athens. They have not been released.
The Lana, previously the Russian-flagged Pegas, was designated under sanctions by the US in February for being owned by a subsidiary of Russian financial institution PSB, blacklisted by Washington as part of sanctions on Moscow following its invasion of Ukraine.
In a US court filing in May, the US government said the Pegas had received a cargo of Iranian oil from an Iranian tanker by ship-to-ship transfer in Iranian waters.
It said the sale of the cargo was “for the benefit” of Iran’s Islamic Revolutionary Guard Corps and its overseas operations wing, the Quds Force, both of which have been designated by Washington as terrorist organisations.
According to a Greek court document seen by Reuters, the US initially requested Greece's intervention against the Pegas on April 20, arguing that the revenue from its cargo “would help support a terrorist group”.
The document said an arrest warrant had been issued by a US court against the Pegas on April 15, which allowed the confiscation of its cargo as the ship's former owner had been sanctioned by the US.
The judges ordered the release of the cargo on the basis that ownership had changed on April 1, before the US request was sent.
The document said none of the cargo's current or former owners had been sanctioned, and no evidence was presented that either was linked to the illegal actions cited by the US.