CHENGDU, Dec. 8 (Xinhua) -- Chengdu, capital city of southwest China's Sichuan Province, reported four new domestically transmitted COVID-19 cases and one asymptomatic case on Tuesday, local authorities said.

According to the Chengdu municipal health commission, one of the newly confirmed patients, a 20-year-old woman, is the granddaughter of two confirmed patients, respectively surnamed Lu and Zhao, who were reported on Monday.

Among the other three cases, a 71-year-old woman and a 68-year-old woman lived in the same neighborhood with Lu and Zhao. A 72-year-old woman was a relative of Lu.

A 69-year-old man surnamed Li, who is a school canteen worker, tested positive for COVID-19 during the city's screening with nucleic acid tests. Li was a close contact of Zhao and diagnosed as an asymptomatic case.

As of 8 p.m. Tuesday, 163 close contacts of the confirmed cases and the asymptomatic case had been traced and placed under medical observation. Of these, swab samples have been collected from 143 people. So far, 73 people have tested negative, with the remaining results still to be released.

Swab samples for nucleic acid tests have been collected from 255,200 people in Chengdu, the commission said.