Biden warns Putin Ukraine attack would bring 'severe costs'

Warnings of Russian invasion stoking 'panic' says Ukrainian President

Efforts to defuse the crisis in Ukraine via a frenzy of telephone diplomacy failed to ease tensions Saturday, with US President Joe Biden warning that Russia faces "swift and severe costs" if its troops carry out an invasion.

"If Russia undertakes a further invasion of Ukraine, the United States together with our allies and partners will respond decisively and impose swift and severe costs on Russia," Biden told Putin, according to the White House.