WASHINGTON, Nov 12 (Reuters) - U.S. Secretary of State John Kerry defended diplomatic efforts to end the war in Syria on Thursday and said all participants in talks in Vienna at the weekend had a responsibility not to dig in their heels.
Speaking before leaving Washington to attend Saturday's talks in the Austrian capital, Kerry cautioned that much work needed to be done and said the United States had yet to resolve its differences with Russia and Iran on the future of Syrian President Bashar al-Assad.
"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."