Nearly two dozen passengers on a Diamond Princess Cruise ship quarantined off the coast of Yokohama Port in Japan have now tested positive for coronavirus and are being hospitalized.

Public Relations Director Negin Kamali confirmed to USA TODAY Wednesday that 10 additional passengers tested positive for the virus during the second phase of health screenings, bringing the total number of people from the ship with coronavirus to 20.

The latest 10 people to test positive include "four Japanese guests, one guest from Taiwan, two Americans, two Canadians and one guest from New Zealand," according to Princess Cruises.

Japanese health officials have reviewed 2,666 guests and 1,045 crew members on board Diamond Princess. Those with symptoms have been disembarked from the ship by public health authorities and transported to local hospitals, Kamali added.

The Diamond Princess will "remain under quarantine in Yokohama," about 17 miles from the Japanese capital of Tokyo, for "at least 14 days as required by the Ministry of Health," the cruise line said Tuesday.

Princess Cruises quarantined the ship after news one of its passengers tested positive for coronavirus.

A guest from Hong Kong disembarked Jan. 25 while the Diamond Princess was docked to visit a local hospital in Hong Kong, where he was diagnosed with coronavirus.

"While on the ship he did not visit the ship’s medical center to report any symptoms or illness," according to a news release published Tuesday, adding that he is in stable condition.

The 14-day cruise, which departed Jan. 20 from Yokohama, was scheduled to return to port Tuesday for disembarkation.

Ship to remain under quarantine for additional 14 days

Princess Cruises' original release said the British-flagged ship was delayed for 24 hours to allow the medical teams to do their work. But now, the Diamond Princess will remain under quarantine for at least two weeks as a precaution.

"The ship plans to go out to sea to perform normal marine operations including, but not limited to, the production of fresh water before proceeding alongside in Yokohama where food, provisions, and other supplies will be brought onboard," the statement said Tuesday. "Guests will continue to be provided complimentary internet and telephone … the ship’s company is working to keep all guests comfortable."

The cruise line added that they will "continue to fully cooperate with and follow the instructions of global medical authorities and the Japanese government."

According to the ship-tracking site Vessel Finder, Diamond Princess is positioned just outside the port.

Coronavirus: The latest on cruise line cancellations and policy changes

As of Wednesday, the outbreak has infected over 28,000 people and killed more than 565, most of them in China.

The U.S. State Department late Thursday elevated its China travel advisory to level 4, recommending that Americans not travel there. That followed the World Health Organization's declaration of a global health emergency over coronavirus.

The Trump administration followed suit Friday and declared the coronavirus a public health emergency in the United States.

And for the first time in a half-century, U.S. health officials have issued a federal quarantine order, compelling 195 Americans evacuated from China to remain at an air base in California for 14 days.

'Do not travel' China advisory:All your coronavirus travel questions answered

What other travel precautions have been taken?

All three U.S. commercial airlines that serve China announced Friday they would temporarily halt all of their flights to and from mainland China. American is suspending flights immediately through March 28; Delta said it would suspend its U.S.-China flights from Feb. 6 through April 30; United is canceling flights from Feb. 6 until March 28. And United and American on Tuesday suspended their flights to Hong Kong through Feb. 20. Nearly a dozen international carriers have also suspended service to China.

Cruise lines have begun to skip China port calls, step up screening measures, cancel sailings and even quarantined an entire ship for what turned out to be a case of the flu. On Thursday, the trade group Cruise Lines International Association pledged that its members will deny boarding to anyone who has traveled through mainland China in the past two weeks, in addition to other precautions.

Chinese authorities have suspended air, road and rail transportation in the area around Wuhan, the city where the virus was first identified, and placed restrictions on other activities throughout the country.

What are the symptoms of coronavirus?

Common Wuhan coronavirus symptoms include fever, cough, shortness of breath and breathing difficulties. Experts are unsure of whether the virus is able to transmit before symptoms appear or after. If it worsens it can cause pneumonia, severe acute respiratory syndrome, kidney failure or even death.

The virus can be spread from animals to people. But it also can be spread by coughing, sneezing and through close contact with an infected person or an object carrying the virus. Experts are still figuring out how long an infected person is contagious as they try to determine a point of transmission.

Health officials on Thursday reported the first U.S. case of person-to-person spread of coronavirus – the second confirmed case in Illinois and sixth in the nation. As of Tuesday, there are 11 reported cases in the U.S.

The first case of person-to-person transmission is the husband of a Chicago woman who developed symptoms after visiting China.

Contributing: Cydney Henderson, Curtis Tate, Dawn Gilbertson, Jayme Deerwester, Morgan Hines, David Jackson, Adrianna Rodriguez, George Petras, Ramon Padilla, Jim Sergent and Janet Loehrke, Grace Hauck, USA TODAY.