The Syrian Observatory for Human Rights said 14 of the dead were civilians and 17 were from the army and security forces.
Assad’s crackdown on more than six months of protests against his rule has killed 2,900, the United Nations says.
The demonstrations themselves have been mainly peaceful, but there have been increasing reports of Sunni conscripts deserting and turning their guns on security forces, dominated by Assad’s minority Alawite sect.
The British-based Observatory said suspected deserters killed eight soldiers in simultaneous attacks on three army posts in the northern province of Idlib.
In the city of Homs, seven civilians were shot dead and another eight people were later killed in clashes between troops and suspected deserters, the group said.
Homs has seen some of the worst violence in recent weeks, including a series of unexplained attacks on local officials and university staff.
The grassroots Local Coordination Committees said in a statement on Monday it had collected names of 180 people it said were killed in Homs in September and another 73 killed in the first nine days of October.
It said the city echoed on Sunday to the sound of bombs, grenades and heavy fighting and blamed authorities for the violence.
Syria says it is confronting foreign-backed terrorist groups who it says have killed 1,100 soldiers and security personnel.
