Hillary Clinton-Kofi Annan discuss Syria

US Secretary of State Hillary Rodham Clinton is meeting former UN chief Kofi Annan to discuss how to salvage his faltering plan to end more than a year of deadly violence in Syria.

Clinton is holding talks with Annan on Friday in Washington at the State Department. They will explore ways to further pressure Syrian President Bashar Assad's regime to comply with the plan or find another way to stop the killing.

The meeting is being held after Syrian troops shelled a rebel-held neighbourhood in the flashpoint central city of Homs.

Activists say the military appeared to be readying to storm the area two days after reports of mass killing in the nearby province of Hama, where about 80 people, including women and children, were shot or stabbed.