"This is a very, very fragile agreement," a senior State Department official said late Friday, telling reporters in a background briefing that the pact "will continue to be a tough sell for the opposition to make to those on the streets."
The accord between the Ukrainian government and the opposition calls for early elections and a return to the 2004 constitution, which gives the country's parliament more power over the makeup of the Cabinet.
The call was initiated by the White House, but the official did not extensively detail the conversation between two presidents long at odds over how to handle the turmoil in a nation that Putin sees as part of his sphere of influence.
The discussion centered on ending the bloodshed in Ukraine and wasn’t a point-by-point outline of how the country should proceed, the administration official added.
Putin has accused the U.S. and western powers of meddling in Ukraine, equating the threat of sanctions to “blackmail” against the former Soviet territory.
The White House earlier Friday said the newly stuck deal did not mean the U.S. would take further economic sanctions off the table.
The State Department official did confirm that Yanukovych had left Kiev for Kharkov, his base of support in the eastern portion of the country. But contrary to reports claiming that the Ukrainian president had fled, the official suggested the leader was attending meetings and maintained control.