The request was delivered through diplomatic channels late on New Year’s Eve to the US State Department, with a copy also sent to the White House National Security Council, according to the report.

The tanker, identified by maritime tracking groups as the Bella 1, has been followed by US forces for nearly two weeks after it left Iran and headed toward Venezuela to load crude oil.

Meanwhile, Washington on Wednesday imposed sanctions on four companies it claimed were operating in Venezuela’s oil sector, along with associated tankers, as President Donald Trump’s administration stepped up pressure on Venezuelan President Nicolas Maduro.

The Russian move comes at a sensitive moment, as Trump has simultaneously sought to advance efforts to broker a peace agreement between Russia and Ukraine.

US officials have argued that the tanker was operating without a valid national flag when first approached by the Coast Guard, rendering it “stateless” under international law and therefore subject to inspection and seizure.

Despite US efforts, the vessel has so far avoided interception.

According to the New York Times, the tanker subsequently sought Russian protection, with its crew painting a Russian flag on the hull and telling US authorities by radio that the ship was under Russian jurisdiction.

The vessel has also appeared in Russia’s official ship registry under a new name, Marinera, listing the Black Sea port of Sochi as its home port.

However, a US official told the newspaper that the Trump administration still considers the ship “stateless,” alleging that it used a fake flag during its initial encounter with US forces.

The White House, the US State Department and the Russian Embassy in Washington did not immediately respond to requests for comment.

Separately, David Tannenbaum, a former US Treasury official responsible for sanctions compliance, said it was “unclear” whether the tanker’s rapid reflagging under Russia would be considered legally valid.

The case forms part of a broader US campaign aimed at restricting Venezuela’s oil exports, which have been critical to sustaining the country’s economy, largely through sales to China.

US authorities have already seized two other tankers in the Caribbean and have said further actions are planned.

In response, Venezuelan President Nicolas Maduro has ordered naval escorts for some departing oil tankers and has considered placing military personnel onboard, a step that could raise the risk of armed confrontation at sea.

Meanwhile, Russia and Venezuela have reinforced political coordination, with Moscow reaffirming its “full support and solidarity with the leaders and people of Venezuela” during a recent call between the two countries’ foreign ministers.