In a fresh drive against visitors who outstay their visas or gain illegal employment, police are targeting areas popular with foreigners in Beijing, such as Sanlitun and the university districts.

The Municipal Public Security Bureau says the 100-day campaign starts today. Foreigners are required to carry passports and accommodation registration documents at all times, in line with Chinese regulations. Beijing is second only to Shanghai in terms of the number of foreigners with residence permits. The number of foreign residents totalled 120,000 at the end of 2011.

A spokesman for the Bureau has dismissed any suggestion that the move is linked to the arrest last week of a British tourist suspected of indecently assaulting a Chinese woman. The man was confronted by several men and later detained in Xuanwumen Dajie, in Xicheng district. Footage of the incident was caught on camera and broadcast on the Web. The man has not been identified by Beijing police but it’s been confirmed he was a tourist with a valid visa