China reported 101 new Covid-19 cases on July 28, the highest since April, the national health commission (NHC) said on Wednesday as Beijing expands nucleic acid testing and contact tracing for new clusters mushrooming in different cities.

Of the 101 new cases, in a record single-day spike, 89 were reported from Urumqi, the capital of the Xinjiang Uyghur Autonomous Region (XUAR), bringing the total number of cases in the province to over 320. Three of the 101 cases were imported, the NHC said.

One case was recorded in Beijing on Tuesday following two cases, including one imported case reported on Monday, breaking the 20-day run of zero infections in the city, which had seen a new cluster breakout in June.

A new outbreak in the northeastern city of Dalian, capital of the Liaoning province, has spilt over to at least nine cities across China including Beijing.At least eight other cities in four provinces – including Tieling, Liaoning; Changchun, Jilin; Hegang, Heilongjiang; and Fuzhou, Fujian – had reported confirmed or asymptomatic cases transmitted from Dalian as of Tuesday, officials said.

Until Tuesday, Dalian had reported more than 50 cases, all linked to a seafood processing centre.

China has intensified Covid-19 testing and contact tracing at all the new outbreak points, health officials have said. Communities have been locked down for testing in some areas.

More than 2.96 million samples for nucleic acid tests of Covid-19 had been collected by Monday in Dalian city in northeast China after new cases began emerging last week, local authorities said on Tuesday.

Beijing, for example, locked down the community where a new Dalian-related Covid-19 patient was reported on Tuesday.

According to official media, the community lifted its epidemic response from Level-III to Level-II and rolled out full testing for all 7,000 households, starting 5 am on Tuesday.

The Tiantongyuan West No.3 community, located in Beijing’s Changping district, where the patient had stayed, has been put under strict restriction with no visitors, food or package delivery allowed.

As of Tuesday, the overall confirmed Covid-19 cases on the mainland had reached 84,060, including 482 patients who were still being treated, with 25 in severe condition.

Altogether, 78,944 people had been discharged after recovery and 4,634 had died of the disease in the mainland, the commission said.

Two new imported cases were reported in Guangdong Province on Tuesday, while Shanghai saw one new imported case.

By the end of Tuesday, a total of 2,056 imported cases had been reported in the mainland.