Washington had pledged to set two sailors free from oil tanker the Marinera shortly after its capture, according to the Russian Foreign Ministry

The US has not yet released two Russian sailors from an oil tanker it seized earlier this month despite promising to do so, Russian Foreign Ministry spokeswoman Maria Zakharova has said.

Russian-flagged tanker the Marinera was captured by the US military on January 7 in international waters northwest of Scotland. American warships had pursued the vessel, previously named Bella 1 and allegedly involved in "violation of US sanctions," all the way from the Caribbean.

Shortly after the seizure of the vessel, Washington pledged to release two Russian nationals of its crew of 28, according to Moscow. The US, however, has still not delivered on its promise, Zakharova said on Thursday.

"We are puzzled and disappointed over the prolonged pause in resolving this important and urgent issue for us, and we hope that this will happen in the very near future and that our citizens will soon be able to return home," she stated at a regular press briefing.

Earlier this week, Russian Foreign Minister Sergey Lavrov said Moscow is still "waiting for our American colleagues to live by their promise." Washington made no public statements on the fate of the sailors.

The Marinera first came in the US crosshairs late last year when it reportedly attempted to approach Venezuela. At the time, the crew refused to accept a US Coast Guard inspection team on board, diverting towards the Atlantic instead. 

During the pursuit, the vessel changed its name and received a temporary permit to fly the Russian flag, granted by the port city of Sochi. Moscow has condemned the seizure of the tanker as a "blatant violation of the fundamental principles and norms of international maritime law" and called out "the use of force against civilian vessels."