Doctors Without Borders says detainees tortured in Libya January 26, 2012 -- Updated 1129 GMT (1929 HKT) MSF says it has treated 115 people with torture-related wounds Some of the patients treated were tortured again, agency says The UN human rights chief voices similar concerns (CNN) -- Doctors Without Borders is halting work in detention centers in the Libyan city of Misrata because detainees are "tortured and denied urgent medical care," the international aid agency said Thursday. The agency known by its French acronym MSF said it has treated 115 people with torture-related wounds from interrogation sessions. Some of the patients treated were tortured again after they were returned to detention centers, according to the agency. "Some officials have sought to exploit and obstruct MSF's medical work," said Christopher Stokes, the agency general director. Patients were brought to us for medical care between interrogation sessions, so that they would be fit for further interrogation. Our role is to provide medical care to war casualties and sick detainees, not to repeatedly treat the same patients between torture sessions. Libyan officials could not be immediately reached for comment. Navi Pillay, the UN High Commissioner for Human Rights, voiced similar concerns about torture in Libya. She said the International Committee of the Red Cross had visited more than 8,500 detainees in about 60 places in Libya between March and December last year. The majority of the detainees are accused of being loyalist of deposed leader, the late Moammar Gadhafi, Pillay said Wednesday. She said the issue is part of difficulties Libya is having in law enforcement and security as the country transitions from the rule of Gadhafi. "The lack of oversight by the central authorities creates an environment conducive to torture and ill-treatment," Pillay said. CNN's Stephanie Halasz contributed to this report.