The Chinese city of Tianjin, with around 14 million people, has tightened exit controls and now requires residents to obtain approval from employers or community authorities before leaving town and a negative Covid-19 test within 48 hours of departure.

The northern coastal city reported 21 domestically transmitted cases with confirmed symptoms, the National Health Commission said, up from three a day earlier.

Tianjin said over the weekend it detected two local infections that contracted with Omicron, according to a Reuters report.