Syria powerbrokers endorse cease-fire deal at talks

Russia, Iran and Turkey presented a united front at the conclusion of two days of talks in Kazakhstan between the Syrian government and the armed opposition, pledging support for the country's shaky cease-fire and a joint mechanism to ensure compliance.

They did not specify how that would work, and continued differences among the warring sides as well as rebel infighting back home threatened to quickly scuttle the deal.

"It's going to be a challenge, it's not going to be easy," the U.N.'s Syria envoy, who mediated between the two sides in the Kazakh capital of Astana, told reporters later.

Russia and Iran, President Bashar Assad's main supporters, and...