National security adviser Jake Sullivan said Sunday that the White House is not considering returning nuclear weapons to Ukraine.

Sullivan made his remarks when questioned about a New York Times article last month that said some unidentified Western officials had suggested U.S. President Joe Biden could give Ukraine the arms before he leaves office.

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.