Twenty-three out of 265,432 samples of nucleic acid testing were positive. The result of gene sequencing for seven positive samples showed the outbreak is highly homologous to the Delta variant of the Covid-19 that prevails in neighboring overseas regions, said Zhai Yulong, Party secretary of Ruili, at a news conference on July 7.

Ruili, a border city in Southwest China's Yunnan province, announced a lockdown in its main urban areas beginning at midnight on Tuesday, requiring all residents to stay at home and most businesses to suspend operation, after the city reported 15 new confirmed locally-transmitted COVID-19 cases and two locally-transmitted asymptomatic carriers on Tuesday.

Jiegao, where all the infections were found, became the country's only high-risk area for COVID-19 starting at 10 am on Wednesday, according to local authorities.

All 17 cases, which involved both people from China and Myanmar, tested positive during citywide nucleic acid testing, after the first infections in this outbreak were reported on Sunday. They were sent to a designated hospital for treatment.

Source: China Daily and Yunnan Release; Xinhua photos; Trans-editing by Wang Shixue