Chinese authorities on Saturday warned that the Delta variant of COVID-19 is likely to spread to more regions in the country. The warning comes after the strain was detected at the Nanjing city airport, one of the busiest airport in the country. In the last couple of months, the Nanjing airport has handled hundreds of summer tourists.

The new wave of the Delta variant strain outbreak in Nanjing city in East China’s Jiangsu Province may continue to spread to more regions in the short term, He Qinghua, a senior official with the National Health Commission was quoted as saying by PTI.

Beijing recently reported its first COVID-19 case after 175 days. Since then several positive clusters have been reported in 15 Chinese cities.

Qinghua told the state-run Global Times that the Delta variant was responsible for the recent outbreak. According to experts, the Delta variant is the most infectious strain of coronavirus yet.

Officials claim that the outbreak spread by cleaners handling a flight from Russia at Nanjing Lukou International Airport had occurred during summer when tourists gathered at scenic spots. The airport, which was shutdown, handles a large passenger flow, especially summer tourists.

“Due to the above three characteristics, the Nanjing outbreak has spread to other regions within and outside Jiangsu Province. There is a risk that it will continue to spread to more regions,” Qinghua said.

Meanwhile, Zhangjiajie, a popular tourist destination in Hunan Province has ordered over 11,000 tourists to take three nucleic acid tests before leaving the city due to the latest resurgence of COVID-19, state-run Xinhua news agency reported.

Tourists have to show negative results from all three tests before leaving the city.

Zhangjiajie closed all tourist sites and upgraded 11 neighbourhoods to medium-risk areas for COVID-19 on Friday. By Thursday night, the city had over 11,900 tourists, the Xinhua report said.

As of Friday, China has officially reported 92,930 since last year of which 971 patients are still receiving treatment and 4,636 died due to the virus.