Zhanjiang in western Guangdong province reported 23 local confirmed COVID-19 cases and 10 asymptomatic cases on Sunday, as the city is experiencing "a rapid increase" in infections.

The city reported 48 infected cases between Friday and noon on Sunday, including 43 in Potou district, two in Suixi county, and three in Lianjiang, a county-level city. Many of the cases involve workers from a warehousing company.

Infections are increasing rapidly, and the risk of community transmission exists, said Wu Guoxiong, deputy mayor of Zhanjiang, at a news conference Sunday night.

The city is carrying out mass nucleic acid tests on Monday in the districts of Chikan, Xiashan, Potou and Mazhang, and the Zhanjiang Economic and Technological Development Zone.

People are required to stay in the city and not leave unless necessary, and provide a negative nucleic acid test result if they do.

Traffic control is imposed on Potou and parts of Suixi, Lianjiang and Chikan, starting at 10 am on Monday.

On Sunday, authorities imposed lockdown, controlled and precautionary zones in the districts of Potou, Suixi, Lianjiang and Chikan.