(CNN) -- Bahraini authorities have released more than 140 detainees, including two ranking former opposition members of Parliament and a prominent opposition lawyer, government officials said.
The two former MP's are members of the largest Shiite opposition group, Al-Wefaq, which resigned from Parliament in February over the killing of pro-reform protesters, most of whom were Shiites.
Former Al Wefaq MPs Matar Matar and Jawad Fairuz were "tortured" while in the custody of Bahraini national security forces, Matar said. Following an interrogation with a military prosecutor, Matar said he, Fairuz and a few others were taken to what he believes was a military site. They were brought to an open area outside and told to raise their hands. Approximately five men began to beat them with sticks for about 30 minutes, Matar said.
The beating took place after Matar said he had completed answering questions from a military investigator. The security forces "didn't want information." They wanted to "send a message that we have a green light," to do whatever they want, Matar said.
Nabeel Rajab, president of the Bahrain Center for Human Rights, said he believes -- based on what people previously in detention have told him -- about 98 percent of people in custody had suffered physically abuse, including beatings, elect shocks and sexual assaults. "No one was immune... very rarely will you find someone who was not abused," Rajab said. There have other been credible allegations of torture by Bahraini security forces from human rights groups, including Physicians for Human Rights.
Bahrain has not yet responded to a query regarding the treatment of the two former MPs while in Bahraini custody.
Matar also claims he was physically abused on one other occasion and he was often interrogated for long hours and denied sleep. My time in detention "was a very tough period for me and my family," he said. But he still feels like a "hostage." They have released us, but they "can come and take us at any time."
Matar, who represented the biggest constituency in Bahrain, and Fairuz, a key lawmaker for Al Wefaq, are charged with spreading lies in an attempt to help overthrow the government. Matar had been held in detention since he was taken from his car by armed men May 2. Fairuz was taken seperately on the same day. Mohamed al-Tajir, a human rights lawyer, was also among those released Sunday.
Bahrain's ruling Khalifa family is Sunni Muslim, but about two-thirds of the country's people are Shiite.
Some detainees were released for legal reasons, according to Bahrain's state media. Suspects in misdemeanor cases had already spent as much time in detention as potential sentences would amount to if convicted, Bahrain News Agency reported. Matar is not sure if he or Fairuz face further court hearings.
Scores of detainees, including at least two women, went on hunger strikes to protest their continued detention without trial, activists said.
Protests demanding political reform and greater freedoms for the Shiite majority began on February 14.
Police turned teargas and firearms on protesters, who had occupied the Pearl Roundabout, an iconic landmark.
Thirty-three people have died since the unrest began, activists say. Four policemen were also killed, according to the Interior Ministry.
A military court has handed down harsh prison sentences from two years to the death penalty for charges including murder and attempting to overthrow the regime.
More than 2,500 people have fired from their jobs for allegedly taking part in the protests, according to the Bahrain Workers' Trade Union.
Bahrain is a strategically important nation to the United States, and it is home to the U.S. Navy's 5th Fleet.
Jennifer Fenton contributed to this report