In a phone call with Russian President Vladimir Putin on Saturday, U.S. President Joe Biden made it clear that if Russia invades Ukraine, the United States and its allies would respond “decisively and impose swift and severe costs,” the White House said.

According to a readout of the hour-long call, Biden told Putin that an invasion would “produce widespread human suffering and diminish Russia’s standing.”

The U.S. remains committed to diplomacy but is “equally prepared for other scenarios,” according to the White House.

The two presidents spoke the day after Biden’s national security adviser, Jake Sullivan, warned that U.S. intelligence shows