TOKYO, Feb. 5 (Xinhua) -- Test results show that 10 people on a cruise ship quarantined off the coast in Japan are infected with the novel coronavirus, the Japanese health minister said Wednesday.

After an 80-year-old passenger from Hong Kong was found to be infected with the pneumonia-causing virus, the ship, the Diamond Princess, has been kept in quarantine off the port of Yokohama, a city south of Tokyo.

Health, Labor and Welfare Minister Katsunobu Kato said at a press conference that of the roughly 3,700 people from 56 countries and regions aboard, 273 people who had close contact with the infected passenger took the virus test, and results for 31 of them had come back.

The ten passengers in their 50s to 80s tested positive and were being sent to hospital, but none had severe symptoms, the minister said.

The government is asking all passengers and crew to stay on the ship for two more weeks from Wednesday, Kato said.

The virus-infected passenger from Hong Kong flew to Tokyo in mid-January and boarded the cruise ship in Yokohama on Jan. 20.