Senior envoys from world and regional powers are to meet once again in Vienna in an effort to salvage stumbling efforts to halt Syria's bloody civil war.

The first major truce in Syria's five-year civil war comes into effect, but Syrian TV says shells hit residential areas of the capital, Damascus.

The United Nations Security Council on Friday unanimously approves a resolution endorsing an international road map for a Syria peace process, a rare show of unity among major powers on a conflict that claimed more than a quarter million lives.