Mao, a teacher in Anji city, Zhejiang province, was picked up by more than 10 police officers yesterday while he mourned his mother who died two days earlier, sources said.

No explanation was given for the arrest, they said.

Mao belongs to the Chinese Democratic Party. Three members of the party tried to register the movement legally in nearby Hangzhou city on June 25 -- the day United States President Bill Clinton arrived in China for a landmark visit.

Zhejiang police had previously detained nine activists involved in the bold bid to set up the party, the first known attempt of its kind in five decades of Communist rule.

Five were promptly released, but Wang Youcai, Wang Donghai, Zhu Yufu and Zhu Zhengming are still in custody.