An additional 65 people on a cruise ship quarantined in Yokohama have tested positive for a new coronavirus, the health ministry said Monday, bringing the number of confirmed cases in Japan -- including some 130 on the vessel -- to more than 150.

As passengers have apparently been under stress during their prolonged isolation on the ship, the Japanese government is planning to allow the elderly and those with chronic illnesses to disembark the vessel quarantined near Tokyo soon, possibly on Tuesday morning, a source familiar with the matter said.

In an effort to prevent the spread of the deadly pneumonia-causing virus in Japan, the health ministry had said earlier it was considering testing all of the approximately 3,600 passengers and crew members aboard the ship when the two-week isolation period ends on Feb. 19.

Once their results were clear, they would be able to leave the vessel.

"We need to properly address the unease and concerns of our citizens," said health minister Katsunobu Kato.

The Ministry of Health, Labor and Welfare had previously said it might be possible for people to disembark from Feb. 19.

The ship has been kept in quarantine since a passenger, who disembarked in Hong Kong, was found to be infected with the virus.

With the death toll in the virus outbreak topping 900 in mainland China, Japan plans to send a fifth flight to Wuhan, a central China city at the center of the outbreak, as early as this weekend to bring home the few remaining Japanese there and in the rest of Hubei Province, Foreign Minister Toshimitsu Motegi said.

The charter plane is set to fly this weekend at the earliest and would be the last for the foreseeable future, Motegi told journalists in Tokyo.

Japan has brought back a total of 763 Japanese and their non-Japanese family members in four chartered planes since late January.

The overall number of confirmed cases in Japan includes 10 people who evacuated from Wuhan on government-chartered flights.

The World Health Organization has not added the number of infected on the Diamond Princess to Japan's total, Kato has said. In the WHO's situation report dated Sunday, 64 earlier confirmed cases were instead counted as being on an "international conveyance."

The Japanese government has provided medication for around 750 of the around 1,850 passengers aboard the Diamond Princess and is working to supply the rest.

The ship departed Yokohama on Jan. 20 and returned on Feb. 3 after visiting Kagoshima, Hong Kong, Vietnam, Taiwan and Okinawa. Those confirmed as infected upon arrival have been hospitalized in Japan.

On Monday, Princess Cruise Lines said it will fully refund all passengers who were unable to disembark in Yokohama due to the virus outbreak.

The refund will include the cost of the cruise, hotel accommodation prior to and following the cruise, onshore excursions and services used aboard the ship.

Passengers who were transported to medical facilities after testing positive for the virus, or hospitalized for other reasons, will also be refunded.

The company will additionally cover all costs incurred by those quarantined aboard the ship since last Tuesday, when passengers were originally scheduled to disembark at Yokohama.

Costs for staterooms on the 16-day cruise range from 295,000 yen ($2,700) to 478,000 yen, according to the company. Suite rooms ranged from 1.08 million yen to 1.38 million yen.

The Ministry of Land, Infrastructure, Transport and Tourism said that 13 of 14 foreign cruise lines scheduled to dock in Japan in February have cancelled their tours.

The remaining cruise ship, the U.S.-operated Ocean Dream, is set to dock at Yokohama on Saturday and Kobe on Sunday.

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