A woman who had been sent to a labor camp in Central China's Hunan province after petitioning for justice for her daughter, who was raped and forced into prostitution at age 11, was released on Friday morning, Xinhua News Agency reported.

Tang Hui, 39, was sent to the Re-education Through Labor Center in the city of Yongzhou on Aug 2 to serve an 18-month sentence for "seriously disturbing social order and exerting a negative impact on society" after she protested in front of local government buildings. Tang complained that the municipal police department had falsified evidence to reduce the sentences of those who kidnapped, raped and forced her daughter into prostitution, the report said.

Labor education, a system established in the 1950s, aims to rehabilitate those who have violated regulations.

Tang on Tuesday applied for administrative reconsideration of the penalty she received, the report said.

After considering her appeal, authorities decided to allow her to leave, because her daughter, now 17, is still a minor and requires her mother's care, provincial publicity officials said.

Tang's claim that the municipal police falsified evidence is also under investigation, the officials said.

Tang's then-11-year-old daughter was kidnapped, raped and forced into prostitution in October 2006. She was forced to provide more than 100 sex services before she was rescued that December, Xinhua reported.

The Hunan provincial Higher People's Court sentenced two of the defendants to death in June. Four others were given life sentences and another received a 15-year term.

Before and after the sentences were handed down, Tang had repeatedly petitioned for justice in front of government buildings and sought the death penalty for all seven people, Xinhua said.

"Tang was dissatisfied with the verdicts, and her petitions have seriously disturbed social order and exerted a very negative impact on society," Xinhua quoted a municipal public security bureau statement as saying.

Tang's case attracted more than 700,000 posts on Sina's Weibo, China's Twitter-like social network, with most of them expressing sympathy for her and appealing for justice.