Almost all flights in and out of Urumqi, capital of China’s far-western Xinjiang region, have been cancelled because of a coronavirus outbreak.
The city has just six confirmed cases with symptoms and 11 asymptomatic infections, official figures show.
Strict measures to rein in the virus include stopping the single metro line and many public buses from operating.
After the pandemic emerged in China in late 2019, the country has driven new infections to consistently low levels.
To avoid a second wave, even small clusters are taken very seriously by health authorities. The initial outbreak in the city of Wuhan was brought under control through some of the world’s strictest lockdown measures.
In Xinjiang, the government is promising decisive measures to contain the outbreak, according to local media reports.
More than 600 flights into and out of Urumqi Diwopu International Airport, more than 80% of Friday’s total, were cancelled. Some social media users in the city say they have been told not to leave their housing estates.
Other social accounts suggested people were being stopped from entering or leaving Kashgar, another city in Xinjiang.
Xinjiang – which is home to the mainly Muslim Uighur people and other Turkic minorities – is already subject to intense state control.
The latest infections began to be detected on Wednesday, the first in the region for months.
A 24-year-old woman tested positive on Thursday after displaying symptoms. Three of her close contacts tested positive. However, they were asymptomatic.
Another asymptomatic case involved a man who travelled from Urumqi to the eastern province of Zhejiang, Chinese state media said.
From Friday, a number of airlines including Juneyao Airlines and Shenzhen Donghai Airlines require all passengers travelling to and from Urumqi to show a negative nucleic acid test taken within seven days.
Passengers must display a “safe to travel” health code, on an app which aims to identify potential virus carriers, the Chinese state-run Global Times says.
It is not clear when restrictions on transport will be lifted. State media put out assurances on Friday that shops were amply stocked with food in what was seen as an attempt to discourage people from panic-buying.