The Chinese province at the epicentre of the coronavirus outbreak has reported a record rise in deaths and thousands more cases under a new diagnostic method, suggesting a much bigger crisis facing China and the world.
It comes as Beijing sacked two top provincial officials after criticism of their handling of the crisis.
Health officials in Hubei province said 242 people had died from the flu-like virus on Wednesday, the fastest rise in the daily count since the pathogen was identified in December.
It takes the total number of deaths across China to 1,367, up 254 from the previous day, the National Health Commission said.
Asian stock markets wobbled and the safe-havens of the Japanese yen, gold and bonds rose after the new Hubei numbers dashed hopes the epidemic was stabilising and the Chinese economy could bounce back quickly.
The spike in the death toll came a day after China reported its lowest number of new cases in two weeks, bolstering a forecast by the country's senior medical adviser that the epidemic could end by April.
Reports in state-run media said provincial Communist Party boss Jiang Chaoliang had been sacked as secretary of the Hubei Provincial Committee, and Ma Guoqiang had been removed as party chief in the provincial capital Wuhan.
The reports did not give a reason for the dismissals but the two are the most high-profile Chinese officials to be removed from duty following the coronavirus outbreak that began in Wuhan late last year.
Dozens of low-level health officials across the country have also lost their jobs for failing to contain the epidemic, which is believed to have emerged from a market in Wuhan where wildlife was traded illegally.
Another 14,840 cases were reported in Hubei alone on Thursday, from 2,015 new cases nationwide a day earlier, after provincial officials started using computerised tomography (CT) scans to look for signs of the virus.
About 60,000 people have now been confirmed to have the virus, the vast majority in China.
Hubei had previously only allowed infections to be confirmed by RNA, or ribonucleic acid, tests which can take days to process.
Using quicker CT scans that reveal lung infections would help patients get treatment more quickly and improve chances of recovery, the Hubei health commission said.
The new diagnostic procedure could explain the spike in deaths, according to Raina McIntyre from the Kirby Institute at the University of New South Wales.
The new testing methodology is only being used in Hubei province, Chinese officials said.
The World Health Organization said on Wednesday the number of cases of infection in China had stabilised but it was too early to say the epidemic was slowing.
"This outbreak could still go in any direction," WHO chief Tedros Adhanom Ghebreyesus said in Geneva.
Chinese scientists are testing two antiviral drugs and preliminary clinical trial results are weeks away but a vaccine could take 18 months to develop.
Hundreds of infections have been reported in more than two dozen other countries and territories, but only two people have died from the virus outside mainland China - one in Hong Kong and one in the Philippines.
The biggest cluster of cases outside China is on a cruise ship quarantined off the Japanese port of Yokohama, where a further 44 cases were reported on Thursday.
Wuhan, a city of 11 million people, remains under virtual lockdown, and other major Chinese cities are facing severe travel restrictions.
Many airlines have suspended flights to China, while countries have imposed bans or quarantine for people arriving from China, disrupting businesses and playing havoc with conferences and sporting events.
Australian Associated Press