Two asymptomatic COVID-19 cases were identified on Monday in Dalang township of Dongguan, Guangdong province, sources with the local health authority said on Tuesday.

The carriers were found during regular tests of people who had visited areas having confirmed cases, a notice issued by the Dongguan health commission said.

The asymptomatic carriers, a man, 33, and a woman, 30, returned to Dalang township on Dec 5, a day after passing through an airport in neighboring Shenzhen.

Local authorities tightened control measures, including traffic restrictions, and required tests for all local residents, the notice said.