Ruili City, in Dehong Dai and Jingpo Autonomous Prefecture, southwest China's Yunnan Province on Wednesday started citywide nucleic acid tests for COVID-19 following the detection of six local cases on Tuesday.

As of Wednesday night at 8:00, over 207,000 samples were collected. 

So far, a total of 317 close contacts of the six patients had been traced and placed under medical observation.

Later, the prefecture's disease prevention and control center ordered four border cities and counties including Ruili to launch large-scale COVID-19 vaccinations to cover all residents aged over 18 starting Thursday.

Earlier, the National Health Commission said a working group it sent has arrived in Ruili to guide COVID-19 epidemic prevention and control.

Stricter restrictions have also been imposed in the city since Tuesday night, including inbound and outbound traffic and all residents were asked to quarantine at home for one week.

(Cover: A medical worker collects a swab sample for COVID-19 test at a community nucleic acid testing site in Ruili City, Yunnan Province, southwest China, September 15, 2020. /Xinhua)