Twenty-one people aboard a mammoth cruise ship off the California coast have tested positive for the new coronavirus, Vice President Mike Pence announced Friday, including 19 crew members.

Pence said the federal government is working with California officials on a plan to bring the ship to a non-commercial port this weekend and the 3,500 passengers and crew members will be tested for the virus.

“We will be testing everyone on the ship and quarantining as necessary,” Pence said. “But with regard to the 1,100-member crew, we anticipate that they will be quarantined on the ship.”

The ship was carrying 3533 people, including at least four Australians.

At this stage it’s unclear if the four Australians on-board are among the confirmed cases.

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Friday’s test results come amid evidence the vessel was the breeding ground for a deadly cluster of at least 10 cases during its previous voyage.

“All passengers and crew will be tested for the virus. Those that will need to be quarantined will be quarantined. Those who will require medical help will receive it,” Pence told the media.

Coronavirus test kits were delivered to the ship on Thursday and samples were collected from 45 people, Princess Cruises said in a statement.

A video posted on social media by the California National Guard showed a military helicopter flying over the ship and lowering the test kits by rope.

Meanwhile, a cruise ship on Egypt’s Nile River with over 150 tourists and local crew was in quarantine Saturday in the southern city of Luxor, after 12 people tested positive for the new coronavirus.

A Taiwanese-American tourist who had previously been on the same ship tested positive when she returned to Taiwan. The World Health Organization informed Egyptian authorities, who tested everyone currently on the ship. Health authorities in Egypt released a statement Friday saying they’d found a dozen Egyptian crew members on the ship had contracted the fast-spreading virus, but did not show symptoms.

The statement said the 12 will be transferred to isolation in a hospital on Egypt’s north coast. The passengers – who include Americans, French and other nationalities – and crew will remain quarantined on the ship awaiting further test results.

The Grand Princess cruise ship was halted near San Francisco on Thursday after a traveller from a previous voyage died of the COVID-19 disease and several passengers and staff members began reporting flu-like symptoms.

Two people who had been on the ship during its previous voyage then contracted the virus. One later died.

The person who died – a 71-year-old man – had been on-board the Grand Princess during its previous voyage between San Francisco and Mexico.

Pence said he believes the numbers of those infected was high among the crew as they had likely been exposed during two previous outings.

The ship had travelled around Hawaii and was making its way back to port, but has now been told it cannot dock until tests confirm whether it is infected.

“The ship will not come on shore until we appropriately assess the passengers,” California Govenor Gavin Newsom said as he declared a statewide emergency on Thursday.

Awe-struck passengers watched the elaborate operation, with their phones at the ready.

“The CDC (US Centers of Disease Control) team along with test samples just air lifted from the ship,” passenger Jim Lange wrote on Instagram.

The samples were sent off to a nearby lab for processing.

Meanwhile, all passengers were asked to stay in their staterooms while the results were pending.

“Guests are receiving meal deliveries in their staterooms by room service, and additional television and movie options have been added to in-room programming,” Princess Cruises said.

“Guests have also been provided complimentary internet service to stay in contact with their family and loved ones, and the ship’s internet bandwidth has been increased.”

Another Princess cruise ship, the Diamond Princess, was quarantined for two weeks in Yokohama, Japan, last month because of the virus, and ultimately about 700 of the 3,700 people aboard became infected in what experts pronounced a public-health failure, with the vessel essentially becoming a floating germ factory.

Three dozen passengers on the Grand Princess have had flu-like symptoms over the past two weeks or so, said Mary Ellen Carroll, executive director of San Francisco’s Department of Emergency Management.

An epidemiologist who studies the spread of virus particles said the recirculated air from a cruise ship’s ventilation system, plus the close quarters and communal settings, make passengers vulnerable to infectious diseases.

“They’re not designed as quarantine facilities, to put it mildly,” said Don Milton of the University of Maryland. “You’re going to amplify the infection by keeping people on the boat.” He said the fallout from the ship quarantined in Japan demonstrates the urgent need to move people off the ship.

“My advice is to get people off and into a safer quarantine environment than a cruise ship,” Milton said.