China has denied it holds political prisoners and said it prohibits the use of torture after facing a United Nations' review of its human rights record.
A Chinese delegation also denied on Wednesday the mistreatment of prisoners held in police stations and deaths in custody.
"The Chinese government prohibits torture and prosecutes any personnel or state organs for torture activities," Li Wensheng, deputy director-general of the legal affairs department in the ministry of public security, told the UN Committee against Torture.
UN experts pressed Chinese officials about persistent allegations that torture is rife in China's police stations and prisons, especially of political prisoners.
"There are no such cases of political prisoners," said Jin Chunzi of the state Ethnic Affairs Commission. "The allegation of cruel treatment of suspects from ethnic minority groups is groundless."
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UN officials questioned the use of electric shocks and rigid interrogation chairs that left inmates in painful positions for long periods.
"We use the interrogation chair to guarantee the safety of the detainee, to prevent the detainee from escaping, from self-harm or attacking other people," said Li. "The chair is sometimes packaged with soft padding to increase a sense of comfort, a sense of safety."
Golog Jigme, a prominent Tibetan monk who broke out of a Chinese detention centre in 2012 and attended the UN session in Geneva after receiving Swiss asylum last month, voiced disappointment.
"Back in Tibet I was used to Chinese propaganda and to hearing lies each and every time there were communications by the Chinese government," he told Reuters.
"I can honestly say there was not the slightest truth in anything they said today. Regarding the interrogation chair, which was highly debated today, they said it was for the detainee's safety. Look at my wounds, on my hands and feet, in fact it was brutal torture."
The United Nations Committee against Torture's regular examination of Beijing's record came after what the group Human Rights in China says has been "a year of massive crackdowns on rights activists and lawyers" on the mainland.