China reported its biggest single-day jump in novel coronavirus deaths on Thursday, as 38 people died within 24 hours. All but one of the deaths were in Hubei.

The spiralling death toll, now 170 nationwide came amidst confirmation that three Japanese evacuated from the outbreak’s epicentre were infected.

This has deepened fears about a global contagion.

The World Health Organization, which initially downplayed the severity of the disease warned all governments to be “on alert” as it weighed whether to declare a global health emergency.

As foreign countries evacuated their citizens from Wuhan, the locked-down city where the virus was first detected, concern over the economic impact has steadily intensified.

Airlines have suspended services to China and companies from Starbucks to Tesla have shuttered stores and production lines.

Chinese authorities have taken extraordinary steps to arrest the virus’s spread, including effectively locking down more than 50 million people in Wuhan and surrounding Hubei province.

But that was yet to pay dividends as the number of confirmed new cases has grown steadily to 7,711, according to the National Health Commission said.

Another 81,000 people were under observation for possible infection.

The pathogen is believed to have been spawned in a market that sold wild game, spreading far and wide by a Lunar New Year holiday season in which hundreds of millions of Chinese travel domestically or abroad.

Japan’s infection rate grew to 11 after three Japanese citizens among more than 200 on an evacuation flight Wednesday tested positive.

Officials had already confirmed two cases in which patients tested positive without having travelled to China, adding to anxiety over human-to-human transmission of the respiratory disease.

“We are in a truly new situation,” Health Minister Katsunobu Kato told parliament.

The fact that two of the three new confirmed Japanese cases showed no symptoms underscored the scale of the challenge for health workers.

The WHO has come under fire after it last week declined to declare a global health emergency.

The global health body’s chief Tedros Adhanom Ghebreyesus expressed regret for what he called a “human error” in the WHO’s assessment.

WHO’s Emergency Committee will meet Thursday to decide whether to declare an emergency — which could lead to travel or trade barriers.

“The whole world needs to take action,” Michael Ryan, head of the WHO Health Emergencies Programme, told reporters in Geneva.