Norway has seized a Russian ship in the Arctic to enforce a $4.2 billion compensation claim won by Ukrainian energy firm Naftogaz over Moscow's seizure of its assets following the 2014 annexation of Crimea, officials said late on Wednesday.

The vessel, the Professor Molchanov, was seized off the Norwegian Arctic archipelago of Svalbard after a 24-hour standoff with the Norwegian Coast Guard, according to Covington, the U.S. law firm representing Naftogaz.

The Svalbard governor's office issued a statement confirming that the ship had been seized and would be held in Svalbard, adding: "The governor will take care of the crew and passengers on board the vessel."

Russia's ambassador to Norway, Nikolai Korchunov, said in a statement that Moscow would pursue the ship's release through legal channels. "We insist on the immediate release of the vessel and on ensuring the safety of its passengers and crew," he said.

It was not immediately clear how many passengers and crew were on board.