The image of the two men meeting, having discarded their military uniforms and put on suits, illustrates how leaders can seize the moment and opt for peace over war.

The deal would allow Kurdish-led forces which hold a quarter of Syria to merge with Damascus, along with regional Kurdish governing bodies.

The United States encouraged its Syrian Kurdish allies to reach Monday's landmark deal with the Islamist-led government in Damascus, six sources said, an agreement that could stave off further conflict in northern Syria at a time of uncertainty over the future of U.