The Nagasaki Prefectural Government on Saturday announced that 57 new coronavirus infections had been confirmed among the crew of an Italian cruise ship docked there.

With testing of all crew members now complete, the new number brings the total aboard the Costa Atlantica to 148, accounting for roughly a quarter of the vessel's 623-member crew. No passengers were aboard.

The infection cluster in Nagasaki comes as hospitals are running out of beds in some parts of Japan, where the national tally of virus cases has risen above 12,800. Some 345 people have died.

Of those infected onboard the Costa Atlantica, only one crew member has been admitted to hospital, NHK said. The others have shown slight or no symptoms and remain on board.

The vessel has been docked in Japan since February for repairs and maintenance after the pandemic prevented scheduled repairs in China. Nagasaki authorities had quarantined the vessel on arrival, and ordered its crew not to venture beyond the quay except for hospital visits.

But prefectural officials said earlier this week that some of the crew had departed without their knowledge and that they were seeking detailed information on their movements.

All but one of the Japanese interpreters on board are foreign nationals and come from more than 30 countries, according to the prefectural government.

On Friday, the operator of the ship said it had decided to send crew members who test negative back to their home countries soon.

The cruise ship infections follow a similar incident earlier this year, when more than 700 passengers and crew tested positive for the virus on the Diamond Princess cruise liner docked in Yokohama.

The Atlantica is operated by CSSC Carnival Cruise Shipping, a partnership between Carnival Corp. and state-owned China State Shipbuilding Corp. The Chinese entity is the majority owner.

Coronavirus cases at sea forced the industry to suspend new sailings in mid-March. Many ships were caught mid-voyage, leading to weeks of drama as companies hustled to get passengers to ports.

Even now, ships around the world still have crews on board.

RELATED PHOTOS An aerial view shows virus-hit cruise ship Costa Atlantica in Nagasaki on Thursday. | KYODO