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 10 and 11, were found in people already under quarantine who were asymptomatic before testing positive, according to the local government. All six cases emerged from a single residential compound.

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.

“Seven provinces reported new infections over the past 14 days, and clustered cases were continuing to increase,” Mi Feng, spokesman for the National Health Commission, said on Monday. China reported only one confirmed case on Tuesday, with no new infections in Wuhan.

Wuhan will enhance the control of residential areas, expand testing among key people and strengthen the management of asymptomatic patients to contain the spread of the virus, according to a statement Sunday by the city’s health commission.

Fears of resurgence were highlighted on Sunday when the northeastern city of 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 heavy restrictions against social gatherings remain in place. Face masks are required for public transport and entering stores and public facilities.