(Reuters) - The United States is not considering returning to Ukraine the nuclear weapons it gave up after the Soviet Union collapsed, White House national security adviser Jake Sullivan said on Sunday.

Russia is closing in on a key town in Ukraine's defensive line made vulnerable by the loss of Vuhledar, the British defence ministry says. Meanwhile, Vladimir Putin has signed off on increasing Russia's military spending to almost a third of the total budget.

Since the November 5, 2024 presidential election, the Biden administration has enormously expanded the scale of direct US military intervention into the Ukraine war.

President Vladimir Putin said on Thursday that Russia would use all weapons at its disposal against Ukraine if Kyiv were to acquire nuclear arms. The New York Times reported last week that some unidentified Western officials had suggested U.

Biden’s Ukraine directive has stirred debate, as some officials worry it will cut too deeply into American stockpiles and jeopardize military needs elsewhere.

The US President's National Security Advisor, Jake Sullivan, has strongly denied reports that the USA is considering reintroducing nuclear weapons to Ukraine. "This is not being considered, no," he stated in an interview with ABC.

Russian President Vladimir Putin formally lowered the threshold for his country's use of nuclear weapons Tuesday, after the U.S. allowed Ukraine to strike inside Russia using American missiles.

The current administration of US President Joe Biden rejects the possibility that Ukraine could obtain nuclear weapons. It will focus on the transfer of conventional weapons, states the National Security Adviser to the President of the United States,