An Iranian-flagged tanker, which the US had previously confiscated around Greece, has unloaded its oil cargo in Syria. 

A ship tracker said on Friday that Lana delivered an oil shipment of around 700,000 barrels in the Syrian port of Banias, ending months of uncertainty about the cargo. 

The seizure from the Lana prompted Iranian forces in May to seize two Greek tankers in the Persian Gulf which were released on November 16. 

Claire Jungman, the chief of staff with US advocacy group United Against Nuclear Iran (UANI), which monitors Iran-related tanker traffic through ship and satellite tracking, said Iran's shipments to Damascus "are regarded as a way of strengthening the country's regional position and are also a major part of the regime's survival strategy". 

The Lana's last reported position on November 20 was anchored off Syria's coast, according to ship tracking on Eikon. The ship, previously called Pegas and renamed Lana in March, had reported an engine problem in April. It was headed to the southern Peloponnese peninsula to offload its cargo on to another tanker but rough seas forced it to moor just off Karystos where it was seized, according to the Athens News Agency.

Syria is undergoing severe fuel rationing as a response to shortages, leading to rolling cuts in the electricity and telecoms sectors. According to UANI analysis, Syria received 1.39 million barrels in shipments from Iran in November, down from 3.5 million barrels in October and 3.7 million barrels in September. 

For over two months, the Lana remained under arrest off the Greek island of Evia. It was tugged to Piraeus following court orders that allowed its release.