China -- where the disease first emerged -- had largely brought domestic transmission under control through lockdowns, travel restrictions and testing, but sporadic regional outbreaks have emerged.

A new cluster in Xinjiang's capital Urumqi in mid-July prompted fresh restrictions. A total of 902 cases have been officially reported in the outbreak.

Officials said earlier this month that they had "effectively contained" the spread of the Urumqi cluster, and there have been no new cases reported in the last eight days.

But hundreds of local residents flooded local social media forums in recent days to complain about harsh conditions, including many being forced to stay home.

After some of these comments were removed -- China's internet is heavily censored -- users tried to flood local forums on the Twitter-like Weibo platform in Beijing, Shanghai and Guangzhou.

Social media users shared photos of front doors sealed with steel crowbars, and locks installed by community workers.

"Why can't prefectures with no cases remove the lockdown? Why do you need to lock down the whole of Xinjiang?" read one comment on Weibo, which received thousands of likes.

"Doors have been sealed, this has brought huge inconvenience to workers and people's lives. Prices of daily items have risen... many things I buy are expired."

Little information has been released by the authorities about the Xinjiang cluster.

Other local governments in China have provided information on patients' movements in granular detail.

Photos circulating on Weibo and WeChat also purportedly showed people chained to community gates with handcuffs, reportedly as a punishment for leaving their homes.

Some residents also wrote that they were forced by authorities to take Chinese medicine daily, and were required to film themselves doing so.

One video from Saturday purportedly showed dozens of high-rise residents in Urumqi yelling from their windows in despair.

Stranded migrant workers, university students, business travellers and tourists have also complained about not being able to leave Xinjiang.

"I have even taken three nucleic acid tests... but community workers won't let me leave," one user wrote on a message board run by the state-run People's Daily.

At a press conference last Thursday, local health officials in Xinjiang said that the epidemic situation remains "complicated and severe".

Around half of Xinjiang's more than 21 million people are ethnic Uighurs and other Turkic Muslims, many of whom complain of decades of political and religious oppression by China's ruling Communist Party, which the government denies.

Activists have accused the Chinese government of incarcerating about one million Uighurs and other Turkic people in Xinjiang camps. Beijing has described them as vocational training centers to counter Islamic radicalism.