Wu, the top epidemiologist at the Chinese Center for Disease Control and Prevention, said on Chinese social media that "foreigners and repatriates" were a potential source of infection.
In a separate message, the expert said that it was best to avoid "skin-to-skin contact with foreigners who have recently (within three weeks) arrived from areas that have reported monkeypox cases."
The risk of a monkeypox outbreak in mainland China remains extremely low, the official said. The viral disease, endemic to Africa, has been spreading globally after several European countries reported flare-ups in spring.