The hospital is one of six with a total of 6,500 rooms being built in Nangong, south of Beijing in Hebei province, the official Xinhua News Agency said.

Also read: China builds new quarantine center as virus cases rise

China had largely contained the coronavirus that first was detected in the central city of Wuhan in late 2019 but has suffered a surge of cases since December.

A total of 645 people are being treated in Nangong and the Hebei provincial capital, Shijiazhuang, Xinhua said. A 3,000-room hospital is under construction in Shijiazhuang.

Virus clusters also have been found in Beijing and the provinces of Heilongjiang and Liaoning in the northeast and Sichuan in the southwest.

The latest infections spread unusually fast, the National Health Commission said.

“It is harder to handle,” a Commission statement said. “Community transmission already has happened when the epidemic is found, so it is difficult to prevent.”

The Commission blamed the latest cases on people or goods arriving from abroad. It blamed “abnormal management” and “inadequate protection of workers” involved in imports but gave no details.

“They are all imported from abroad. It was caused by entry personnel or contaminated cold chain imported goods,” said the statement.

Also read: Dozens quarantined after coronavirus found in frozen food in China

The Chinese government has suggested the disease might have originated abroad and publicized what it says is the discovery of the virus on imported food, mostly frozen fish, though foreign scientists are skeptical.

Also Saturday, the city government of Beijing said travelers arriving in the Chinese capital from abroad would be required to undergo an additional week of “medical monitoring” after a 14-day quarantine but gave no details.

Nationwide, the Health Commission reported 130 new confirmed cases in the 24 hours through midnight Friday. It said 90 of those were in Hebei.

On Saturday, the Hebei government reported 32 additional cases since midnight, the Shanghai news outlet The Paper reported.

Also read: China clamps down in hidden hunt for coronavirus origins

In Shijiazhuang, authorities have finished construction of 1,000 rooms of the planned hospital, state TV said Saturday. Xinhua said all the facilities are due to be completed within a week.

A similar program of rapid hospital construction was launched by the ruling Communist Party at the start of the outbreak last year in Wuhan.

More than 10 million people in Shijiazhuang underwent virus tests by late Friday, Xinhua said, citing a deputy mayor, Meng Xianghong. It said 247 locally transmitted cases were found.

Meanwhile, researchers sent by the World Health Organization were in Wuhan preparing to investigate the origins of the virus. The team, which arrived Thursday, was under a two-week quarantine but was due to talk with Chinese experts by video link.

The team’s arrival was held up for months by diplomatic wrangling that prompted a rare public complaint by the head of the WHO.

Also read: WHO team arrives in Wuhan to investigate pandemic origins

That delay, and the secretive ruling party’s orders to scientists not to talk publicly about the disease, have raised questions about whether Beijing might try to block discoveries that would hurt its self-proclaimed status as a leader in the anti-virus battle.