State media on Friday showed crews leveling earth, pouring concrete and assembling pre-fabricated rooms in farmland outside Shijiazhuang, the provincial capital of Hebei province that has seen the bulk of new cases.

That recalled scenes last year, when China rapidly built field hospitals and turned gymnasiums into isolation centers to cope with the initial outbreak linked to the central city of Wuhan.

Also read: Schools in China's Wuhan to start new semester from Sept 1

China has largely contained further domestic spread of the coronavirus, but the recent spike has raised concerns due to the proximity to the capital Beijing and the impending rush of people planning to travel large distances to rejoin their families for country’s most important traditional festival.

The National Health Commission on Friday said 1,001 patients were under care for the disease, 26 of them in serious condition. It said that 144 new cases were recorded over the past 24 hours. Hebei accounted for 90 of the new cases, while Heilongjiang province farther north reported 43.

Nine cases were brought from outside the country, while local transmissions also occurred in the southern Guangxi region and the northern province of Shaanxi, illustrating the virus’ ability to move through the vast country of 1.4 billion people despite quarantines, travel restrictions and electronic monitoring.

Also read: What WHO researchers in Wuhan are trying to learn

Shijiazhuang has been placed under virtual lockdown, along with the Hebei cities of Xingtai and Langfang, parts of Beijing and other cities in the northeast. That has cut off travel routes while more than 20 million people have been told to stay home for coming days.

In all, China has reported 87,988 confirmed cases with 4,635 deaths.

The spike in northern China comes as World Health Organization experts prepare to collect data on the origin of the pandemic after arriving Thursday in Wuhan, where the coronavirus was first detected in late 2019. Team members must undergo two weeks of quarantine before they can begin field visits.

Two of the 15 members were held up in Singapore over their health status. One of those, a British national, was approved for travel Friday after testing negative for the coronavirus, while the second, a Sudanese citizen from Qatar, had again tested positive, the Foreign Ministry announced.

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

The visit was approved by President Xi Jinping’s government after months of diplomatic wrangling that prompted an unusual public complaint by the head of WHO.

That delay, along with Beijing’s tight control of information and promotion of theories the pandemic began elsewhere, added to speculation that China is seeking to prevent discoveries that chisel away at its self-proclaimed status as a leader in the battle against the virus.

Also read: COVID-19 not necessarily crossed from animals into humans in Wuhan: WHO expert

Scientists suspect the virus that has killed more than 1.9 million people since late 2019 jumped to humans from bats or other animals, most likely in China’s southwest.

Former WHO official Keiji Fukuda, who is not on the team, cautioned against raising expectations for any breakthroughs from the visit, saying that it may take years before any firm conclusions can be made.

“China is going to want to come out avoiding blame, perhaps shifting the narrative, they want to come across as being competent and transparent,” he told The Associated Press in an interview from Hong Kong.

Also read:  Wuhan lab director trashes COVID-19 conspiracy theory

For its part, the WHO wants to project the image that it is “taking, exerting leadership, taking and doing things in a timely way,” said Fukuda.

In Wuhan, street life appeared little different from other Chinese cities where the virus has been largely brought under control.

In a riverside park, senior citizens gathered to drink and dance while residents had praise overall for the government’s response to the crisis.

“Other countries are not very supportive and don’t pay attention to the pandemic, people go out arbitrarily, and they hang out and gather together, so it’s especially easy for them to be infected,” resident Xiang Nan said. “I hope they can stay home, and reduce traveling ... don’t let the pandemic spread further anymore.”

China is also pushing ahead with inoculations using home-developed vaccines, with more than 9 million already vaccinated and plans for 50 million to have the shot by the middle of next month.