Biden warns Putin: Ukraine attack will bring 'swift and severe costs'

U.S. President Joe Biden warned his Russian counterpart Vladimir Putin in a phone call Saturday that the United States "will respond decisively and impose swift and severe costs on Russia" if it invades Ukraine.

According to a readout from the White House, Biden stressed that "while the United States remains prepared to engage in diplomacy, in full coordination with our Allies and partners, we are equally prepared for other scenarios."

"President Biden was clear that, 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," the statement said.

The White House also said Biden had "reiterated" to Putin that attacking Ukraine "would produce widespread human suffering and diminish Russia's standing."

The two presidents talked for just over an hour and apparently made no breakthrough in defusing the standoff between the West and Russia over the deployment of air, land and sea forces to surround neighboring Ukraine on three sides.

The call was "professional and substantive," a senior US official told reporters. But "there was no fundamental change in the dynamics unfolding now for several weeks."

The official said Washington had put forward proposals that would "enhance European security and also address some of Russia's stated concerns," while also vowing to respect Ukraine's sovereignty.

"It remains unclear whether Russia is interested in pursuing these goals diplomatically, as opposed to using force. We remain committed to keeping the prospect of de-escalation through diplomacy alive. But we're also clear eyed about the prospect of that, given the readily apparent steps Russia is taking on the ground," the official said, speaking on condition of anonymity.

"The stakes of this are too high not to give Russia every chance" to stand down, the official said. "So, as always, we continue along two paths."

The senior US official said that "Russia is already finding itself increasingly isolated from the wider world and more depending on China."