President Vladimir V. Putin warned President Biden on Thursday that any economic sanctions imposed on Russia if it were to take new military action against Ukraine would result in a “complete rupture” of relations between the two nuclear superpowers, a Russian official told reporters on Thursday evening.
A 50-minute phone call that Mr. Putin requested, and which both sides described as businesslike, ended without clarity about Mr. Putin’s intentions. He has massed 100,000 or so troops on the border with Ukraine, and issued demands for the North Atlantic Treaty Organization and the United States to pull back their forces in the region, but apparently has not decided whether to order an invasion.
Mr. Biden, for his part, “made clear that the United States and its allies and partners will respond decisively if Russia further invades Ukraine,” according to a terse White House account of the call.
American officials declined to discuss any of the substance of the discussion, insisting that, unlike the Russians, they would not negotiate in public. But both sides appeared to be trying to shape the diplomatic landscape for talks that will begin in Geneva on Jan. 10, and then move to Brussels and Vienna later in the week in sessions that will include NATO allies and then Ukraine itself.