The tanker, which was in Karystos, a port in the south of the Greek island of Euboea, left around 07:00 (04:00 GMT) in the direction of Piraeus, according to Marine Traffic, a site specializing in maritime traffic.
On April 19, the Greek authorities seized the Russian tanker Pegas, renamed Lana, off the island of Evia, under European sanctions linked to the war in Ukraine. According to reports at the time, the tanker was carrying 115,000 tons of Iranian oil.
The Greek authorities had subsequently announced that the ship and its crew would be released. But the oil had instead been withheld at the request of the US Department of Justice, and a process of transferring the cargo to a vessel chartered by the United States had been initiated.
The United States imposes economic sanctions on Iran, which particularly affect its oil exports.
The Iranian Foreign Ministry had requested via the International Maritime Organization (IMO) the Greek government to release the tanker while accusing the United States of «having unloaded the cargo from the ship». In retaliation, two Greek oil tankers were seized by Iran.
A Greek regional court had ordered on June 9 the return to Iran of the confiscated oil.
According to the Greek agency Athens News, some 60,000 tonnes of crude are concerned, out of the total cargo initially transported by the Lana.
Uncertainty remains, however, over who will bear the costs of transferring oil currently stored on another tanker currently stationed off Piraeus to the Lana.