US President Barack Obama held a "constructive" phone call with Russian President Vladimir Putin, Friday as he pressed for swift implementation of a deal framed to end Ukraine’s crisis

US President Barack Obama held a "constructive" phone call with Russian President Vladimir Putin, Friday as he pressed for swift implementation of a deal framed to end Ukraine's crisis.
  
The call came at a prickly time in US-Russia relations with the two sides at odds over Ukraine, Syria and other issues, but also after Obama took pains to reject the idea that a new Cold War-style confrontation was brewing.
  
A senior US official described the call as "constructive" but also warned that the agreement reached in Kiev between the government and top opposition leaders was "very, very fragile."
  
Putin and Obama agreed that the Ukraine agreement needed to be swiftly implemented and that all sides needed to refrain from violence. "President Putin affirmed that Russia wants to remain part of the implementation process.  They also talked about the need to stabilize the Ukrainian economy and to get Ukraine back on a peaceful path," the official said, on condition of anonymity.
  
The call also touched on other issues including Syria, where Russia backs President Bashar al-Assad, to the fury of the United States, and the Sochi Winter Olympics.

The White House gave an initial welcome to the deal and praised European Union diplomats who helped to broker it.