Syria crisis: Your experience
Shooting has erupted close to an advance team of UN observers in the town of Arbeen, on the outskirts of the Syrian capital Damascus, activists say.
Videos posted online appear to show anti-government protesters ducking as snipers open fire.
Activists say dozens of people have died in the latest shelling of opposition areas in Homs in central Syria, and Idlib in the north.
Ahmad spoke to BBC News via Skype about the recent violence.