Passengers began disembarking on Wednesday from a cruise ship docked off Yokohama, Japan, as a two-week quarantine of the vessel was coming to an end even as a major coronavirus outbreak on board continued unabated.

An initial group of about 500 people were to leave the boat on the first day of what the Japanese authorities have said will be a three-day operation to offload those who have tested negative for the virus and do not have symptoms. Passengers who shared cabins with infected patients have been ordered to remain on the ship.

Several countries have arranged charter flights to take their nationals home after they leave the boat. Most if not all of these passengers face an additional two-week quarantine in their home countries.

The disembarkation is taking place even as at least 542 passengers aboard the ship, the Diamond Princess, have been infected with the virus. On Tuesday, the authorities announced an additional 88 cases on the ship, which originally carried about 3,700 passengers and crew members.