KUNMING, March 31 (Xinhua) -- The city of Ruili in southwest China's Yunnan Province on Wednesday launched a city-wide nucleic acid testing for COVID-19 after new cases were reported.

According to the city's epidemic prevention and control headquarters, starting from 8 a.m. Wednesday, all residents in the urban areas will be quarantined at home for a week. During the period, all business premises except supermarkets, pharmacies and farm produce markets will be closed.

Ruili found one positive case during regular COVID-19 testing among high-risk groups on March 29, and another eight positive cases in the following tracing. After further testing, six were diagnosed as confirmed cases and three as asymptomatic, said the provincial health committee.

The tracing and testing of their close contacts are underway.

A working group sent by the National Health Commission has arrived in Ruili to guide COVID-19 epidemic prevention and control, according to the commission.

According to the disease control and prevention center in Dehong Dai and Jingpo Autonomous Prefecture, which administers Ruili, local health authorities will launch large-scale vaccine inoculations to cover all residents aged over 18 in four border cities and counties including Ruili starting Thursday. Enditem