Ukraine’s ambassador to the United States was quoted as saying on Friday that Ukrainian nationals were among members of the crew of the Russian-flagged tanker Bella-1, seized this week by US forces.

Olha Stefanishyna, quoted by the Interfax Ukraine news agency, said Ukrainian diplomats were in contact with US authorities to ensure consular access to the crew members.

“The embassy has the situation under control and is using all necessary means to maintain contact with the Ukrainian citizens,” Stefanishyna was quoted as saying.

The Bella-1, recently renamed the Marinera and registered as a Russian vessel, was seized in the North Atlantic this week.

The US has seized five ships in recent weeks as part of efforts to curb Venezuelan oil exports. The Olina was seized in the Caribbean on Friday.

The Russian Foreign Ministry said on Friday that the United States had released two Russian crew members from the Marinera, expressed gratitude to Washington for the decision and pledged to ensure the return home of crew members.

Russia’s Transport Ministry said on Wednesday it had lost contact with the Marinera after US naval forces boarded it near Iceland.