Wuhan, where the global coronavirus epidemic first started, reported its first new infections since the Chinese city ended its 76-day lockdown on April 8.
The six locally transmitted cases, reported on May 9 and 10, were found in people already under quarantine who were asymptomatic before testing positive, according to the local government.
Although the new cases are few and appear under control, they serve as a reminder of the risks China faces as it tries to reopen an economy that has seen its worst contraction since 1992.
Fears of resurgence were highlighted on Sunday when the northeastern city Shulan, which borders North Korea, was partially locked down after 11 new infections were discovered.
Many cities in China still don’t allow cinemas and bars to operate and strict restrictions against social gatherings remain in place. Face masks are required for public transport and entering stores and public facilities.