At least four activists were sent to re-education camps for "disrupting the social order" over the past month as China prepares for the impending once-a-decade change in leadership.

The Hong Kong-based organization Human Rights in China on Wednesday identified the convicts as Mao Hengfeng, Tong Guojing, Shen Yongmei and Cai Fufang in a communique.

The husband of Mao, Wu Xuewei, told HRIC that the communist authorities told him in late October that his wife had been sent to the re-education center for two "illegal acts" this year in Shanghai, referring to her participation in tributes for two other activists, including one who died in custody.

The other three prisoners were also punished for participating in one of the events that Mao was party to, according to what Tong's husband, Zhang Fangxian, told HRIC.

All four were what are known here as petitioners - citizens invoking an antique imperial system to ask the central government for justice after they have exhausted all legal pathways at the local and regional levels.

The majority of these complaints are related to forced expropriations, physical mistreatment, the deaths of relatives in custody and other cases of corruption.

HRIC spoke out about the detentions a day before the start of the 18th Communist Party Congress, from which the Chinese leaders for the next decade emerged and for which the authorities undertook extreme harassment measures against activists or dissidents.

Amnesty International said last Friday that at least 130 people have been arrested or subjected to various forms of restrictive measures since September. EFE