Obama, Putin held 'constructive' talks on Ukraine: U.S. official

WASHINGTON (Reuters) - U.S. President Barack Obama held a "constructive" phone call with his Russian counterpart Vladimir Putin on Friday and agreed it was important that Ukraine's peace agreement be implemented quickly and that Ukraine's economy is stabilized, a senior State Department official said on Friday. "They agreed that the agreement reached today needed to be implemented quickly, that it was very important to encourage all sides to refrain from violence, that there was a real opportunity here for a peaceful outcome," the official told reporters on a conference call. (Reporting by Lesley Wroughton; Editing by Chris Reese)