Tianjin, which neighbors Beijing and has a population of 13 million, began citywide nucleic acid testing Sunday morning, according to local authorities. All the residents are advised not to leave their communities.

The sample collection and testing is expected to be completed within 24 hours, said a notice issued by the authority. Those who don't take the tests will see their health code turn "orange."

Between Feb 24 and March 26, a total of 793 confirmed COVID-19 cases have been reported and the youngest patient was a eight-day-old baby.

The city didn't release all of the sources of this round of outbreaks that has hit 14 districts. The origin of the epidemic in Wuqing district was confirmed to be a male case returning from Langfang, Hebei province.

On Saturday, the city also announced multiple measures to relieve local companies' burden during the ongoing pandemic.

They include tax and rental fees deductions for micro, high-tech, and private companies.