Fears of an epidemic on board a cruise ship off Yokohama came to a head Friday as the health ministry reported 41 more coronavirus infections, bringing the total to 61 so far.

Health minister Katsunobu Kato said the new cases on board the Diamond Princess emerged from the remaining 171 samples taken from 273 passengers who showed symptoms or who had close contact with symptomatic passengers.

Kato said the health ministry is planning to expand the testing to cover seniors and people with pre-existing conditions.

Elsewhere, authorities in Taiwan confirmed the same day that a cruise ship off Naha, Okinawa Prefecture, that was not allowed to dock in Japan will be allowed to return to Keelung, near Taipei, according to local media reports.

The approval came a day after Taiwan’s ban on cruise ships took effect amid the mass outbreak on the Diamond Princess.

The 41 infected passengers reported Friday on the Diamond Princess range in age from their 20s to their 80s. Twenty-one of them are Japanese citizens, he said.

The 41 infected passengers reported on Friday range in age from their 20s to their 80s. Twenty-one of them are Japanese citizens, he said.

Princess Cruises, the ship’s operator, said the rest included eight Americans, five Canadians, five Australians, an Argentinian and a Briton. They will be taken to hospitals in Kanagawa, Tokyo, Saitama, Chiba and Shizuoka prefectures, according to the health ministry.

Authorities earlier this week had already confirmed that 20 people on the ship had been infected, including one crew member.

“I think the number has increased as a result of people being in a confined space, inside the cruise ship, making repeated contact” over a period of time, Kato said.

About 3,700 passengers and crew members were on the Diamond Princess when it was put under a two-week quarantine off Yokohama on Wednesday. They won’t be allowed to disembark until at least Feb. 19, Princess Cruises said.

The ship came to the attention of medical authorities when it was revealed that a man who left it on Jan. 25 in Hong Kong was infected. Two people who had close contact with him later tested positive for the coronavirus.

The health ministry and Defense Ministry sent a total of ten doctors and five nurses to the ship to perform checkups and other medical procedures. In addition, up to 80 Self-Defense Forces troops will be dispatched to assist the medical team there, the Defense Ministry said.

Including confirmed cases on the ship, the total number of infections in Japan is 86, putting the country second behind China.

But Kato disputed the tally and said the government’s official count does not include the 61 aboard the Diamond Princess because they had not entered Japan prior to being diagnosed with the virus. The health ministry insists the official count is 21, a figure that excludes four asymptomatic cases.

When asked, the health minister flatly denied his explanation was designed to play down a perception that Japan may be unsafe.

The count of 21 gives a clearer picture of the reality of the situation in Japan, Kato said.

In its daily report, the World Health Organization classified the people infected with the coronavirus on the ship as “cases on an international conveyance,” and said Japan’s official tally is 25.

Meanwhile, a fourth flight chartered by Japan to pick up people in China’s Wuhan and Hubei province returned to Tokyo with 198 evacuees on Friday morning. Wuhan is ground zero for the outbreak. They will be brought in to a government facility in Wako, Saitama Prefecture, if they pass the medical screening.

On the flight, 77 Chinese and two Taiwanese with Japanese ties were allowed to board.The Chinese government hadn’t in principle allowed any of its citizens to leave on the three previous flights.

Chief Cabinet Secretary Yoshihide Suga said that no one was denied a seat after going through China’s preboarding medical screening but four were not feeling well upon arrival.

He also said several Japanese still wish to come back but that scores have opted to stay.

“We think the vast majority of Japanese citizens residing in Hubei province who wanted to come home have done so, after the fourth flight dispatch,” Suga said.

In the meantime, transportation minister Kazuyoshi Akaba revealed the ministry had asked the luxury cruise ship Westerdam from Hong Kong not to call in Japan because it is believed that people infected with the virus are on board.

Prime Minister Shinzo Abe announced on Thursday evening that foreign citizens on the Westerdam would be barred from entering the country. The ship was set to arrive in Okinawa on Saturday. Japan will be taking similar actions to other foreign ships carrying people potentially infected with the coronavirus, Abe said.

The ship has five Japanese among the passengers and crew, Suga said Friday. Its operator, Holland America Line, said it is “quickly working to develop alternate plans.”

During a debate in the Diet, Kato said Japan has 60 facilities that can conduct mass testing of samples to detect the coronavirus. Their capacities vary: The National Institute of Infectious Diseases can test up to 260 samples at a time but an institution in Kanagawa Prefecture can only test 20.

“We are currently working to enable testing at universities or private testing facilities,” Kato said. “Also, we want to respond by making the health and safety of the people on the ship our highest priority.”

RELATED PHOTOS Officials in protective suits Friday wait beside the Diamond Princess, a cruise ship anchored at Daikoku Pier in Yokohama where 41 more people tested positive for the new coronavirus. | KYODO

A woman unfolds a Japanese flag that reads "shortage of medicine" on the Diamond Princess cruise ship on Friday. The cruise liner is currently quarantined in the port of Yokohama as a result of the coronavirus. | REUTERS

Officials carry supplies for the Diamond Princess cruise liner docked at Yokohama port on Thursday. Forty-one more people on the quarantined ship have tested positive for the new coronavirus, it was announced Friday. | KYODO