Beijing began a crackdown on foreigners illegally entering, residing or working in the city on May 15.

The campaign, which will run until the end of August, will include household checks in areas of high concentrations of foreign residents, as well as on-the-spot street checks that will require foreigners to present valid identification, according to a spokesman for the Beijing Municipal Public Security Bureau.

Police authorities had opened a tip-off hotline and would tighten reviews of visa applications during the period, the spokesman said.

Foreigners found to be violating relevant laws may face penalties ranging from fines or detention to deportation, according to the police.

Official statistics show Beijing is home to about 120,000 foreigners.

According to Chinese law, it is illegal for foreigners to enter China without a valid visa issued by Chinese authorities or a legal passport, as well as through unofficial ports of entry.

It is also illegal for foreigners to live in China on expired visas or residence permits, as well as acquire paid jobs without a proper work visa.