July 29 (UPI) -- Clusters of COVID-19 cases have emerged in several cities in China after months of no official reports of outbreaks.
Many of the cases are being traced to visitors to a live show held in Hunan Province last week and an airport in Nanjing.
Domestic tourists who visited Zhangjiajie National Forest Park in Hunan tested positive for the Delta variant of the novel coronavirus in different parts of the country after leaving the province, China Central Television reported.
More than 3,000 people attended the indoor show, which included dance performances by artists wearing costumes representing Hunan's minority groups. Chinese media footage shows the audience either not wearing masks or with their masks lowered.
An outbreak of the Delta variant reported earlier this week at an airport in the eastern Chinese city of Nanjing, home to more than 9 million people, has been linked to visitors from the northeastern city of Dalian. The travelers visited the Nanjing airport before going to Zhangjiajie, according to The Paper.
Nanjing is the epicenter of China's latest wave of outbreaks. A total of 174 cases of COVID-19 have been confirmed nationwide since last week, with many of the infections reported among people who visited the airport then flew to other parts of the country, including Guangdong, Sichuan and Liaoning provinces.
"The recent spike in infections in the city can be attributed to the special location of the outbreak and the highly contagious nature of the [Delta] strain," vice director of Nanjing's center for disease control and prevention Ding Jie said Tuesday, according to CNN.
The city of Beijing reported its first COVID-19 case in nearly six months Wednesday, with a second case in the city confirmed Thursday afternoon, the report said.
The Beijing cases were a husband and wife who traveled to a city in Hunan Province, the same location as the indoor show that drew thousands of spectators.
Chinese authorities have said they are conducting mass testing in Nanjing, but cases continue to rise in Jiangsu Province, according to CNN.
Last week, China's National Health Commission said the country has administered more than 1.5 billion doses of domestically developed COVID-19 vaccines.