Five feminist activists remain in police custody in China after authorities detained at least eight across the country in the run-up to International Women's Day.
Lu Jun, a board member for rights group Women Centre, said the detained activists include Li Tingting, Wei Tingting, Wang Man and Wu Rongrong, the founder and executive director of the Hangzhou-based rights group.
Mr Lu said their lawyers have not been able to reach them since their detention on Friday.
He added the women had planned to observe International Women's Day by putting up leaflets about sexual harassment in Beijing, Hangzhou and Guangzhou.
He said the activists have previously observed the day without interference.
Police in Beijing and Guangzhou made no comment.