The view of Potala Palace in Lhasa city, Southwest China's Xizang Autonomous Region. Photo: IC

The COVID-19 cases detected in Lhasa, capital of Southwest China's Xizang (Tibet) Autonomous Region was believed to be a family cluster infection caused by imported Omicron subvariant BA.2.76, said a local health official based on gene sequencing tests at a press conference on Tuesday morning.

World heritage sites Potala Palace and Norbulingka, as well as Tibet Museum in Lhasa have been temporarily closed to visitors on Tuesday with undetermined reopening date. 

Lhasa has reported 18 positive cases since Sunday and started to implement "static management" in the medium and high-risk regions. 4 cases were found earlier in Ngari Prefecture's Burang county. The 22 cases are all related to Xizang's Xigaze city, home to about 800,000 people.

Xizang region has started mass nucleic acid testing in cities of Lhasa and Xigaze and Ngari Prefecture. Cities of Lhasa and Xigaze are currently carrying out the first round of mass testing and will conduct the second round of testing on Wednesday. Counties of Burang, Gar and Zanda in Ngari Prefecture are undergoing the third round of testing. 

Some 601 close contacts of the positive cases have been traced and put under quarantine. Cities of Lhasa, Xigaze and Qamdo have set up 4,004 beds in three makeshift hospitals to take in asymptomatic and mild cases. There are seven designated hospitals across Xizang region for treating the infected elderly and cases with severe symptom and underlying diseases.

The omicron infection is not a "big flu" with much higher transmission risks, emphasized Yan Zhouzhong, deputy director of Lhasa health commission, urging the local public to receive COVID-19 vaccines especially the third booster shot against severe cases and deaths. 

Before the 18 cases detected in Lhasa and 4 cases found earlier in Burang county, Xizang region had reported only one COVID-19 case during the past three years, who was a traveler from Wuhan of Central China's Hubei Province, which reported the first COVID-19 case in China.