File photo: CGTN

The number of people who have tested positive for the new coronavirus on a quarantined ship off Japan's coast has risen to 355, the country's health minister said Sunday.

"So far, we have conducted tests for 1,219 individuals. Of those, 355 people tested positive. Of those, 73 individuals are not showing symptoms," Katsunobu Kato told a roundtable discussion on public broadcaster NHK -- a rise of 70 from the last government toll.

The new figures came as the United States was preparing to evacuate some of its citizens from the Diamond Princess, which has been in quarantine since February 5 in the port of Yokohama, near Tokyo.

Hong Kong also said it would offer its 330 citizens on board the chance to take a charter flight back.

"Based on the high number of COVID-19 cases identified onboard the Diamond Princess, the Department of Health and Human Services made an assessment that passengers and crew members onboard are at high risk of exposure," the US embassy said in a letter to its passengers.