A coronavirus outbreak in the Chinese province of Xinjiang has spread to a second city, one day after authorities announced “wartime” anti-pandemic measures in a district in the city of Urumqi.

On Monday, the national health commission reported 22 new cases, five of which were imported. One case was reported in the ancient Silk Road city of Kashgar, in north-western Xinjiang, while the rest were in the nearby city of Urumqi.

At least 47 people diagnosed with Covid-19 in Xinjiang were in the city of Urumqi. However, the Urumqi city government has not provided a public update since 15 July.

On Sunday, the national health commission said 13 people in Xinjiang were reported to have the virus, 16 on Saturday, and one on Friday.

Measures announced on Sunday for the Tianshan district of Urumqi included mass health screenings, and some public transport and most flights into the city were stopped on Saturday. Group activities have been suspended and people were warned against unnecessary travel outside the city.

District authorities have also “strengthened [housing] compound management”, including tighter controls over who goes in and out, carrying out a comprehensive disinfection of the public areas of the community, providing contactless delivery services and help purchasing daily necessities.

According to the publicly released reports by Chinese health authorities, Xinjiang – a sparsely populated region – has been largely spared from the outbreak, which began in Hubei province and spread rapidly.

The sudden rise in cases has prompted speculation online that authorities were covering up an outbreak in Xinjiang, a province that continues to be the subject of international focus due to the persecution of its Uighur minority.

Chinese social media users pointed out there had been no reported cases in Xinjiang for 149 days until 16 July.

On 17 July, the hashtag “Xinjiang Urumqi epidemic” reached 34m views on the Chinese social network Weibo before dropping sharply. Some commenters accused Xinjiang state media Tianshan of blocking comments on its posts.

Beijing, meanwhile, has gone 14 days without a case of local transmission, and city authorities on Sunday said they were downgrading the emergency response level from 2 to 3. The move is largely symbolic, with many measures remaining in place including mandatory social distancing, temperature checks and 14-day quarantines for passengers arriving from abroad.

China also reported on Monday that 5,370 people had been arrested for pandemic-related crimes between January and June. More than 40% were charged with fraud, the state prosecutor’s office announced on its official microblog. A further 15% were charged with obstruction of law enforcement, with others accused of producing and selling fake and shoddy goods, creating public disturbances and transporting and selling endangered species.

China has strengthened protection for wild animals after the emergence of the virus, which may have originated in bats before jumping to humans via an intermediary species such as the anteater-like pangolin.

No specific figures were given for those accused of violating quarantine rules and travel restrictions, although there have been relatively few such cases reported in official media.

Although faulted for allowing the virus to spread from Wuhan, China’s government has been credited with imposing rigid and sometimes draconian measures to contain the outbreak, and people have overwhelmingly complied with orders to wear masks, display certificates of good health and maintain social distancing.

Additional reporting by Pei Lin Wu