Kerry in talks with Russian leaders over Syria

The United States and Russia pledged Tuesday to set aside more than two years of differences over Syria's civil war, saying they'd convene an international conference later this month to try to corral President Bashar Assad's regime and the rebels into talks on a political transition.

Yet even as leaders from both countries hailed their joint strategy as proof of enhanced U.S.-Russian cooperation, it was unclear how their plan might now prove effective in ending a war that has become even more dangerous in recent months. There are accusations the Assad regime has used chemical weapons, Israeli airstrikes on weapons convoys and American threats to begin arming the rebels.

The outcome of more than five hours of meetings in Moscow involving U.S. Secretary of State John Kerry and President Vladimir Putin and Foreign Minister Sergey Lavrov essentially bring diplomatic efforts to halt Syria's violence to a point they were about a year ago. The former Cold War foes, who've split bitterly over how to halt the conflict, said they'd work to revive a transition plan they laid out in June 2012, yet never gained momentum with Syria's government or the opposition. They said this time they were committed to bringing the Syrian government and rebels to the negotiating table.

Speaking about the U.S. strategy, Kerry suggested the Obama administration would consider holding off on any possible plan to provide weapons to vetted units of the Syrian opposition if a peace strategy takes hold in the coming weeks.

That appeared to be a minor concession to Russia, which has argued vehemently against any foreign governments providing military assistance for fear it would aid extremists.

Kerry also appeared to back down from the outright U.S. demand that Assad step down in the transition. Although the secretary maintained that he, personally, couldn't see how a leader responsible for such widespread abuses could remain in power as part of a peace deal.

Kerry said the international plan for a transition agreed to last year in Geneva must not be a "piece of paper," but rather "the road map" for peace.