Hundreds Tortured in Syria, Human Rights Group Says BEIRUT, Lebanon - The Syrian government said Thursday that it had released more than 500 prisoners who were not involved in "terrorist" acts. A human rights group said, meanwhile, that it had compiled evidence that thousands of other detainees were languishing in government prisons and secret detention centers where, the group said, torture was routine. The official Syrian news agency released an image that it said showed freed detainees on Thursday. Shaam News Network, via Associated Press An amateur video from Ar Rastan, Syria, was said to show victims' mothers during a meeting with members of the Arab League's mission. The group, Avaaz, also said that its researchers had gathered the names of at least 617 people who had died under torture in government installations since the beginning of the uprising against Syria's president, Bashar al-Assad. The group's estimate of the number of the detainees - 37,000 - was more than double the tally provided by the Local Coordination Committees, another activist group, which said Thursday that it had documented the cases of more than 16,000 detainees. With journalists rarely allowed to travel around Syria freely since the unrest started, it was impossible to confirm either report. Arab League observers currently in Syria are supposed to monitor promises by the government to release political prisoners. The observers, however, are not allowed to visit military sites, where rights groups believe that the government has transferred hundreds of detainees to hide them from the observers. The Syrian state news agency said Thursday that the government had released almost 4,000 prisoners since Nov. 5, "all of whom were not involved in the shedding of Syrian blood." Opposition groups continue to contend that the observers have been ineffective, failing to win the release of enough prisoners, the withdrawal of government tanks and artillery from many cities or an end to the bloodshed. On Thursday, in a statement, the Arab League announced a buttressing of the mission, saying that 110 observers would be added by the end of the week. The Arab League is set to discuss the first report by the leader of the observer mission, Lt. Gen. Muhammad Ahmed al-Dabi of Sudan, on Sunday. Several activist groups reported deadly violence on Thursday near Deir Ezzor in eastern Syria, including the security forces firing on demonstrators and clashes between the army and soldiers who have defected to the opposition. At least 12 people were killed, according to the Local Coordination Committees and Avaaz. The government also reported several attacks on its forces, saying two people had been killed in an attack on a police station in Dara'a. In a separate episode, a retired colonel and his son were killed after gunmen opened fire on their car near Homs, the state news agency reported. To compile its report on prisoners, Avaaz said it confirmed deaths with three sources. It said that detainees - held in makeshift detention centers in places like soccer stadiums and movie theaters or at regular prisons - reported torture techniques that included sleep deprivation and electric shocks. One detainee reported that people who had made videos or took photographs of protests and were held at the Homs Military Hospital often had their arms, wrists or fingers broken. Some prisons were crammed far beyond capacity, including the Homs Central Prison, where detainees went on strike this week to protest the conditions inside, Avaaz said.