A surge of coronavirus cases is sweeping across China. It comes after the government eased its strict anti-infection measures on December 7.

Case numbers have been growing since last week in Shanghai, where staff shortages are causing delays in delivery services.

Shanghai has the largest Japanese population among cities in China. The city's Japanese consulate-general says the virus is spreading among employees at Japanese and other businesses.

But officials at the mission say there have been no reports suggesting production lines or distribution have been severely affected by the surge. They say this is partly because there are no longer restrictions on people's movements.

Chinese media outlets report infections are spreading among civil servants in several provinces, including Henan and Shandong. They say local authorities have closed their offices to the public and are calling on citizens to use online services instead.

Officials of Chengdu in the inland province of Sichuan said at a news conference on Thursday they have set up 300 fever clinics across the city. They said up to 42,000 people a day are visiting the facilities.