A Princess Cruises ship is locked down in a Japanese port, with 3,700 people quarantined on board after it was revealed that an infected passenger flew into Tokyo and spent a few days on the ship.

Medical officials are going room-by-room to check each guests’ temperature and medical condition, Japan’s health ministry said in a statement.

So far 10 people on the ship, which is sitting in Yokohama Bay, have been confirmed with the coronavirus.

There are still more than 100 samples awaiting test results. There are”¯2,666”¯guests and”¯1,045”¯crew members on board, Princess Cruises said in a statement.

The infected patient: The infected former passenger on the cruise ship is an 80-year-old man from Hong Kong. He went to mainland China for a few hours on January 10, but did not visit healthcare facilities or seafood markets — meaning he likely contracted the virus from another person.

On January 17, he flew into Tokyo, and began coughing on January 19. He boarded the cruise in Yokohama on January 20. He disembarked the cruise when it stopped in Hong Kong on January 25, and sought medical attention on January 30.

He is currently in a stable condition.