Russia has deployed a submarine and other naval vessels to escort an empty, ageing oil tanker that has been trying to evade the US blockade near Venezuela, the Wall Street Journal reported on Tuesday, citing a US official.

The tanker, formerly known as Bella 1, has been evading interception since the US Coast Guard attempted to board and seize it in December, following Washington's blockade of sanctioned oil shipments to and from Venezuela.

Russia has asked the US to stop pursuing the vessel, the Journal said, citing three other US officials.

Reuters could not immediately verify the report. The White House and the US Coast Guard did not immediately respond to a request for comment outside regular hours.

On Tuesday, the Russian Foreign Ministry said it was monitoring the situation surrounding the tanker "with concern", the Journal said, citing Russian state news agency RIA.

The US Southern Command, which oversees military activities in Latin America and the Caribbean, said in a post on X on Tuesday that it "remains ready to support US Government agency partners in standing against sanctioned vessels and actors transiting through this region." It did not mention the Journal report or the Russian submarine.

The US Coast Guard has continued to trail the ship into the Eastern Atlantic, where it is now sailing about 300 miles south of Iceland toward the North Sea, the Journal added, citing AIS positioning.

The tanker changed its name to the Marinera and switched its registration to Russia, the Journal said.

US President Donald Trump on Tuesday to refine and sell up to 50 million barrels of Venezuelan oil that had been stuck in Venezuela under US blockade, in a further sign that Washington is coordinating with the Venezuelan government since capturing President Nicolas Maduro in a raid last weekend.