The World Health Organization (WHO) said on Monday the spread of coronavirus cases that had no history of travel to China could be "the spark that becomes a bigger fire" as people across China trickled back to work after an extended Lunar New Year holiday.

The death toll from the epidemic rose to 908, all but two in mainland China, on Sunday as 97 more fatalities were recorded — the largest number in a single day since the virus was detected in the city of Wuhan in December.

The Diamond Princess cruise ship with 3,700 passengers and crew on board remained quarantined in the port of Yokohama, with 65 more cases detected, taking the number of confirmed cases from the Carnival Corp.-owned vessel to 135.