A middle-aged mentally ill man injured two foreigners in downtown Shanghai on Sunday, raising concerns about the management of psychotic people in big cities.

The Chinese man, identified by police as Song, attacked the two foreigners with a fruit knife at 2:45 pm in the city's Hongkou district. He was wielding a small club in the other hand, police said.

Both victims are male and work in the city. Police said they suffered minor injuries and one of them left a hospital after receiving stitches.

One victim, an Australian, was riding an electric bicycle near the crossing of North Sichuan Road and Wujin Road when he was attacked in the face.

The other victim, from the United States, was riding a bicycle at the corner of Zhapu Road and Haining Road when the barefoot attacker cut his right ear.

"The two locations are very close. After the incident, both victims were sent to local hospitals immediately," a police officer, who declined to give her name, said on Monday.

Chinese media quoted witnesses as saying that after the incident, the attacker remained calm and dropped the knife on the ground.

Local police said the attacker has been sent to a mental health center for psychiatric testing.

The incident has helped quell doubts about a work manual released by local health authorities recently, proposing to screen people suspected of having mental health problems, in Shanghai.

Earlier this month, the Shanghai health bureau released proposed guidelines on the prevention and treatment of mental health problems, requiring community health service centers to survey people who stayed in the city for six months or longer to determine if they are mentally ill and report them if they are.

Local residents have been asked to report people who they suspect are psychotic, or who have psychotic behavior that could include behaving abnormally, avoiding contact with the outside world, being over-talkative, not attending work or school, or spending most of their time at home.

The manual was the subject of some ridicule, with many people pointing out that people who spend considerable time on their computer, sleeping and watching television could be suspected of being mentally ill just because they spend time inside — an increasingly popular way of life in China.

The screening is a way to help local health authorities identify people with mental health problems and provide timely detection and intervention, health officials said.

People diagnosed with mental problems will be included in a community-based network for further diagnosis and treatment. Local community hospitals and doctors will make regular visits and provide psychological rehabilitation for patients. Those with serious mental illnesses will be sent to local mental health hospitals for professional treatment, according to the manual.

The patients' personal information and the records of their mental illness will be well-protected, and the treatment will be carried out only with the approval of patients and their guardians, authorities said.

Contact the writer at wanghongyi@chinadaily.com.cn