Police said it would be hard to track down all the group's members
Police in Hong Kong are trying to trace members of a group on the social networking site Facebook which appeared to call for a mass suicide.
Nearly 190 people joined group, which allegedly urged them to kill themselves on 21 December, said Chinese media.
Attention was first drawn to the site by a student who told social workers about it after attempting suicide.
The group has been since taken down but police said they were trying to contact all members and its creator.
The South China Morning Post said the person who started the group had written that it was "meant to be an inside joke", where people talked humorously about ways to take their lives.
But some of the 188 people who joined it had reportedly written posts in which they shared possible suicide methods and asked for people to join them in dying.
Chinese state media reported that photographs had been posted on the site of a female member of the group attempting to kill herself at school.
"The police are not going to inspect online activities, but we will try to contact people who have logged onto the page," Li Jianhui, chief police officer in Yuen Long district, told China Daily.
But he said it would be hard to track down every member as many of them may not be based in Hong Kong.
Mr Li said police and education officials would also be working with parents and teenagers on suicide prevention programmes.
Encouraging a person to kill themselves or assisting their suicide is punishable with a prison sentence of up to 14 years under Hong Kong law.
The South China Morning Post quoted Hong Kong's Undersecretary for Security, Lai Tung-kwok, as saying the government was monitoring the case.