China reported a rise in new virus cases Monday, possibly denting optimism that disease control measures including isolating major cities might be working, while the operator of a cruise ship in Japan reported dozens of new cases.

The mainland death toll rose by 97 to 908 in the 24 hours through midnight Sunday and 3,062 new cases were reported. That was up 15% from Saturday and broke a string of daily declines. A government spokesman had said Sunday those declines showed containment measures were successful.

The operator of a cruise ship quarantined in Yokohama, near Tokyo, said an additional 66 cases were found aboard. That is in addition to 70 reported earlier.

Health Minister Katsunobu Kato said the Japanese government was considering testing all 3,711 passengers and crew on the Diamond Princess, which would require them to remain aboard until results are available. Health authorities are scrambling to deliver medicine requested by more than 600 passengers.

“We are doing the utmost to keep everyone in good health,” Kato said.

The fatality toll from the new virus has passed the 774 people believed to have died in the 2002-03 epidemic of severe acute respiratory syndrome, another viral outbreak that originated in China. The total of 40,171 cases on the mainland of the new virus vastly exceeds the 8,098 sickened by SARS.

More than 440 cases have been confirmed outside mainland China, including two deaths in Hong Kong and the Philippines.

The British government declared the virus a “serious and imminent threat to public health,” which it said gives authorities powers to forcibly detain infected people if necessary. The change comes after a British man who caught the virus in Singapore in January appeared to be linked to at least seven other confirmed cases in Europe.

China has built two hospitals and sent thousands of extra doctors, nurses and other health care workers to Wuhan, the city of 11 million people in central China that is the epicenter of the outbreak. Most access to Wuhan was suspended Jan. 23. Restrictions have spread to cities with a total of 60 million people.

Businesses are gradually reopening following the Lunar New Year holiday, which was extended to discourage travel in an attempt to contain the virus, but they face heavy losses.

Zhang Peng, who works for a livestreaming company in Beijing, went to the office for the first time since the holiday. The company checked employees for fever and handed out masks.

“I thought the situation is fairly good now,” Zhang said. “I went to work by subway today and underwent various checks in the station. And my company did a good job of prevention and control.”

Iris Ke, who works for an advertising company, said she plans to wait until next week to go back to the office.

“We just need to have a little more sense of self protection,” said Ke. “Life goes on anyway. How come we stop going outside or stop working simply because of fear of disease? We can’t do that.”

At the Sanyuanli market in Beijing, the Chinese capital, shoppers in face masks mixed with delivery drivers who were collecting orders of meat, fruit and vegetables. Stalls were stocked with pork, mutton, seafood and vegetables.

“The number of customers here is down a lot, maybe by more than half,” said Liu Ying, who sells walnuts, cashews and other specialties. “But you can see a lot of people calling in orders, so we’re slowly getting busy again.”

Global stock markets slid Monday following warnings that investor optimism the disease and its economic impact were being brought under control might be premature. Market indexes in London, Frankfurt, Tokyo and Hong Kong declined. Shanghai closed higher after spending most of the day in negative territory.

China’s central bank announced a 300 billion yuan ($43 billion) fund to make low-interest loans to producers of medicine and medical supplies or other companies involved in fighting the virus.

Over the weekend, the government promised tax cuts and subsidies to farmers, supermarkets, producers of medical supplies and companies that contribute to anti-disease work.

China’s leaders are trying to keep food flowing to crowded cities despite the anti-disease controls and to quell fears of possible shortages and price spikes following panic buying after most access to Wuhan and nearby cities was cut off.

Consumer inflation spiked to an eight-year high of 5.4% over a year earlier in January, driven by a 4.4% rise in food costs, the government reported Monday. Food prices rose 1.4% from the previous month.

“It appears that supply disruptions and hoarding due to the coronavirus outbreak helped to keep food prices elevated during the week after Chinese New Year, when they would normally drop back,” Julian Evans-Pritchard of Capital Economics said in a report.

Organizers of the Hong Kong Arts Festival on Monday canceled all of its more than 120 planned music, dance and drama performances, including two concerts by the Boston Symphony Orchestra. The festival was due to start this week and run through mid-March.

Meanwhile, the mother of a physician who died last week in Wuhan said in a video released Sunday she wants an explanation from authorities who reprimanded him for warning about the virus in December.

The death of Li Wenliang, 34, prompted an outpouring of public anger. Some postings left on his microblog account said officials should face consequences for mistreating Li.

“We won’t give up if they don’t give us an explanation,” Lu Shuyun said in the video distributed by Pear Video, an online broadcast platform.

The video shows flowers in her home with a note that says, “Hero is immortal. Thank you.”