UN-Arab League envoyarrived in Damascus on Saturday to press President Bashar al-Assad for a ceasefire and a political solution to a year of unrest in which thousands of people have been killed.
Annan's trip to Damascus followed a violent day in which activists said Assad's forces killed at least 72 people as they bombarded parts of the rebellious city of Homs.
Arab foreign ministers were also due to hold talks in Cairo with Russian Foreign Minister Sergei Lavrov. Russia and China vetoed a U.N. draft resolution last month which would have backed an Arab League plan calling for Assad to step aside.
Current UN chief Ban Ki-moon said“I very strongly urged Kofi Annan to ensure there must be an immediate ceasefire".
The conflict is now one of the bloodiest of the Arab Spring, with the U.N. saying more than 7,500 people have been killed. Activists put the number at more than 8,000.