Opposition fighters are clashing with Syrian government forces in the capital, Damascus, for a second day, activists said today.
Activists and residents said the fighting in several areas is among the heaviest since the uprising against President Bashar Assad's regime began in March last year.
The Britain-based Syrian Observatory for Human Rights and Syria-based activist Mustafa Osso said today's clashes were concentrated in the districts of Kfar Souseh and Tadamon.
One resident said gunfire and sporadic explosions could be heard this morning.
Damascus is tightly controlled by Mr Assad's forces, although there have been sporadic clashes in the capital in recent months.
The fighting comes as UN special envoy Kofi Annan is due to visit Moscow to discuss the Syrian crisis with Russian leaders.