[Updated at 2:44 p.m. ET] Deaths mounted in Syria on Friday as world powers plan crucial talks about the conflict there.

Soldiers and security forces killed 135 people on Thursday and Friday, said the Local Coordination Committees of Syria, an opposition activist group.

The group said most of the people were killed in Homs and dozens also died in Hama and Daraa. CNN cannot independently confirm events in Syria because it is limited from reporting on the ground. Of those reported dead, 18 were children and eight were women.

In violence Friday in the Daraa province town of Nawa, 11 civilians died at the hands of pro-regime militias. The assault occurred during a funeral procession for a high school student whom security forces killed Thursday.

"The regime's forces encircled the procession and responded with intense gunfire which led to additional martyrs. ... (President Bash al-Assad's) security forces and thugs raided the private hospital in the town and attempted to kidnap the wounded," the group said. It said activist Bashar Abu al-Sal, popular for leading chants in demonstrations, was among the 11 dead. Dozens also were wounded, it said.