(CNN) -- Syrian government snipers and other forces stalked opponents in homes and neighborhoods Friday in a campaign of gunfire, shelling and arrests amid mass protests against the rule of President Bashar al-Assad, an opposition group said.

At least 37 people died in the violence, including 10 in Damascus, seven in Idlib, six in Hama, five in Homs, four in Aleppo, two in Deir Ezzor, two in Daraa and one in a Damascus suburb, according to the opposition Local Coordination Committees of Syria.

Three of the victims in Idlib died from torture after their arrest several days earlier, the organization said. The three had been held at an environmental development center that had been transformed into a jail, the group said.

Government tanks shelled the town of Sharaei, destroying at least five homes, the LCC said.

In the town of Anadan in Aleppo province, security forces stormed a home and killed a man, his wife and son, the opposition group said. Local activists said they will be buried after Friday prayers.

In Damascus Countryside province, forces raided homes in the town of Qaboun, activists said.

In Habeet, in Idlib province, activist Ahmed Salem told CNN by telephone that participants in a "huge protest" were chanting the names of students who died in violence Thursday at Aleppo University. He said security forces were firing on people approaching the city gates, but no forces were inside the town.