Washington, US: US Secretary of State John Kerry urged nations gathering for Syria peace talks to show flexibility and said the chances of a diplomatic solution hinged in part on the military balance.
Speaking before he headed to the Vienna talks, which he said would include officials from Iran, Russia, Saudi Arabia, Turkey and Europe, Kerry defended diplomatic efforts to end the civil war even as he acknowledged a solution was not near.
"I cannot say this afternoon that we are on the threshold of a comprehensive agreement," Kerry told a Washington think tank. "America's message to each (participant) is that we all have a responsibility, not to dig in our heels but to take the next forward step - so that the bleeding can stop."
He also said that the emergence of any eventual agreement will depend on ground struggle as well as on bridging the fundamental U.S. disagreement with Russia and Iran on the future of Syrian President Bashar al-Assad.
The United States argues that Assad must go following any political transition, while Russia says his fate should be decided by the Syrian people in an election.
