Thousands of people face spending the next fortnight stuck on a luxury cruise ship quarantined off the Japanese port of Yokohama, after initial results showed 10 passengers have tested positive for the novel coronavirus, The Guardian reports.

The Diamond Princess, with more than 3,700 passengers and crew onboard, had been prevented from sailing on Monday after an 80-year-old passenger who had travelled on the vessel late last month tested positive after he arrived home in Hong Kong.

Of a further 273 people on board who have since been tested following health screenings, 31 results had come back – and of those 10 were positive, according to Japan’s health minister, Katsunobu Kato. It is not clear if more tests will be carried out.

Also on Wednesday, February 5, health checks began on 1,800 passengers and crew on a second cruise ship docked in Hong Kong, after 30 staff members reported symptoms including fever, according to Reuters.

Hong Kong’s health department said that 90% of the passengers were Hong Kongers and no mainland Chinese were on board. Previously, three mainland Chinese that had been on the ship between 19 and 24 January, and were found to have contracted the virus. No passengers have been able to leave the World Dream ship, operated by Dream Cruises, without permission.

The respiratory illness has killed 490 people in mainland China and infected more than 23,000.