Almost all flights in and out of Urumqi, the capital of the Xinjiang region in the far west of China, have been canceled due to a coronavirus outbreak.
The city has only six confirmed cases with symptoms and 11 asymptomatic infections, according to official figures.
Strict measures to control the virus include stopping the operation of a single subway line and many public buses.
After the pandemic in China emerged in late 2019, the country has brought new infections to consistently low levels.
To avoid a second wave, even small groups are taken seriously by health authorities. The initial outbreak in Wuhan City was controlled under some of the strictest blockade measures in the world.
In Xinjiang, the government promises decisive measures to contain the outbreak, according to local media reports.
More than 600 flights in and out of Urumqi Diwopu International Airport, more than 80% of Friday’s total, were canceled. Some social network users in the city say they have been told not to leave their housing estates.
Other social accounts suggested that people were prevented from entering or leaving Kashgar, another city in Xinjiang.
Home to mainly Muslim Uighurs and other Turkish minorities, Xinjiang is already subject to intense state control.
The latest infections began to be detected on Wednesday, the first in the region in months.
A 24-year-old woman tested positive Thursday after showing symptoms. Three of her close contacts tested positive. However, they were asymptomatic.
Another asymptomatic case involved a man who traveled from Urumqi to eastern Zhejiang province, Chinese state media said.
As of Friday, various airlines, including Juneyao Airlines and Shenzhen Donghai Airlines, require all passengers traveling to and from Urumqi to show a negative nucleic acid test taken within seven days.
Passengers must display a “safe to travel” health code, in an application that aims to identify potential virus carriers, says Global Times, administered by the Chinese state.
It is unclear when transport restrictions will be lifted. State media said on Friday that the stores were heavily stocked with food in what was seen as an attempt to discourage people from buying panic.
News of the Xinjiang coronavirus outbreak and government response there quickly came.
We had just learned of a case and suddenly most of the flights in and out of Urumqi had stopped and the subways were not working. The response seemed too overwhelming to justify a single infection, prompting questions on social media about whether officials may be underestimating the numbers.
However, the count went up on Friday morning and, crucially, health officials in Urumqi say they have at least 135 people under medical observation.
This has become the pattern in China. When a cluster appears, the government will use many resources to control it through mass testing, localized restrictions, and the closure of transport links to block the outbreak wherever it occurs. This strategy appears to have worked in other cities, such as Beijing in June.
In Xinjiang, there is the added sensitivity of controversial detention camps where hundreds of thousands of mostly ethnic Uighurs have been interned as part of a massive “de-radicalization” program. If the coronavirus were to enter one of those camps in the same way as in prisons here, the possibility of widespread infection would be considerable.
The latest figures from China show 10 new confirmed cases, nine of them imported from abroad, the country’s health authority said.
So far, confirmed infections in China are 83,622, with deaths at 4,634. Beijing has not reported new cases for 11 days in a row.
There has been international concern that deaths in China have not been sufficiently reported. Questions have also been raised, by the US government and others, about Beijing’s handling of the epidemic, particularly in its early stages.
But China has also been praised for taking decisive steps to curb the spread of the virus.
The Chinese Foreign Ministry has repeatedly accused the Trump administration of trying to distract itself from its own problems to tackle the crisis in an election year.
The United States has more infections and deaths than any other nation.