Restrictions in the central business district of Futian and Longhua, home to a major campus of electronics maker Foxconn, have been extended until Sunday, while residents in several areas across the city were asked to work from home if possible.

Most of the city's nearly 18 million population is now subject to COVID controls.

On Thursday evening, officials sought to quell rumours that the city of nearly 18 million would undergo a full lockdown as it did for a week in March, and said people could leave and return to their homes with a 24-hour proof of testing.

So far, authorities have largely avoided shutting down offices and factories.

On Friday, officials reported 87 new locally transmitted COVID-19 infections in Shenzhen on Sept. 1, up from 62 a day earlier. Of those, eight were outside quarantine areas.

(Reporting by David Kirton, Editing by Raju Gopalakrishnan)