A Chinese researcher has warned of a new threat to public health and morality — naked Internet chatting. Up to 20,000 Chinese Internet users log on to chatrooms each night in which users in various states of undress talk to each other with the help of Web cams, the Shanghai Daily newspaper said Tuesday, citing China Youth Association researcher Liu Gang.

"At first, we thought if was merely a game for a few mentally abnormal people," the paper quoted Liu as saying. "But as our research continued, we found the problem was much larger than expected," Liu said.

Participants in the sites download chat software and attach video cameras to their computers, the paper reported. They then "talk with others while exposing themselves and performing provocative poses," it said.

China has more than 87 million Internet users, the second largest after the United States.