Beijing has reported seven local COVID-19 cases, six of which are from Daxing district.
Daxing has strengthened prevention measures, including the launch of sweeping district-wide nucleic acid testing, banning residents from leaving Beijing, and shutting down schools and nursing homes.
At least five residential communities in Daxing have entered lockdown, requiring people to quarantine at home, starting from Wednesday, said local authorities.
All public places in the five affected communities were ordered to shut down, including business buildings, shopping malls, restaurants, construction sites and cinemas.
Trains and buses have been ordered to limit their passenger numbers to 75% of capacity, while metro stations in the affected areas will be closed, according to authorities.
The local cluster outbreak in Daxing is serious, bringing the district's prevention and control work to a critical point, said Beijing's top leaders at a meeting held on Tuesday night.
Beijing also ordered all those who have entered the city since December 10, 2020 to be screened to find the origin of the outbreak.
Daxing's outbreak started on Monday after two residents were found to be infected with coronavirus, leading to a wider search for their close contacts in the capital city.