The Greek Coast Guard announced on Tuesday that it had delayed a Russian oil tanker off the island of Obia in accordance with EU sanctions against Moscow due to its military invasion of Ukraine.
The United States welcomed the move and said the Russian tanker was carrying Iranian crude oil.
The European Union (EU) earlier this month imposed new sanctions on Russia to deal with what the Kremlin calls "special military operations," banning Russian vessels from entering EU ports, with a few exceptions.
According to Reuters, the Pegasus tanker carrying the Russian flag with 19 crew members stopped near Christos on the southern coast of Uvia.
The Russian embassy in Athens, the capital of Greece, wrote on Twitter that it was investigating the incident and was in contact with Greek officials.
"The tanker was seized in accordance with EU sanctions," said a source in the Greek shipping ministry.
A State Department spokesman also said that Washington welcomed Greece's efforts to impose sanctions in response to Russia's brutal and unjustified attack on Ukraine.
"We are aware of reports that the tanker was carrying Iranian crude oil," he added. The U.S. official, however, did not elaborate further on the reports and how they were verified.
Meanwhile, a Greek Coast Guard source said the ship's oil cargo had not been confiscated.
The Pegasus tanker, which was renamed Lana last month, recently reported that its engine needed to be repaired. According to the Athens news agency, the tanker turned to the southern peninsula of the Peloponnese to transfer its cargo to another tanker, but weather conditions forced it to dock near Christ, where it was captured.
The U.S. organization, which monitors the movement of Iranian-owned tankers via satellites, says the Pegasus tanker carries 700,000 barrels of Iranian crude oil, which were loaded at the oil terminal off the Iranian island of Siri in August.
According to the organization, the Pegasus oil tanker intended to unload its cargo at a Turkish port before leaving for Greece.
Reuters quoted eyewitnesses as saying that the Pegasus oil tanker was still docked in the Bay of Christos until Tuesday afternoon.