United States to press Russia on Syria's Assad

With a fragile truce in place and Europe pressing the warring sides to keep going with negotiations, a state department official said Kerry wants to "get down to brass tacks" on the question of President Bashar al-Assad's future.

The head of Syria's delegation in Geneva sounded positive after meeting European Union foreign policy chief Federica Mogherini, a rare encounter with a senior Western figure.

"For the first time, I can tell you that we were able to break the impasse, maybe in the form and a little bit in substance," he said, adding that the government would attend the next round of talks after legislative elections in government-held areas on April 13.

He did not give any details and Mogherini said the EU had not changed its position on the need to start a political transition in Damascus. The Saudi-backed opposition, whose chief delegate also met Mogherini, has said there are no points of convergence.

The negotiations have been bogged down on a series of issues and one delegate said it was up to Kerry and Putin to create a breakthrough.

"We're waiting for a U.S.-Russian accord to solve the (key) issue once and for all. Until they resolve it this process will drag on," Randa Kassis, who heads up a Moscow-backed opposition group, said.

While the United States want Assad to step aside, Russia says only the Syrian people can decide his fate at the ballot box and has bristled at any talk of regime change.

Kerry is holding talks with Putin at the Kremlin on March 24, in a meeting arranged after the Russian leader's surprise announcement on March 14 that he was partially withdrawing his forces from Syria.