The Navy reported three coronavirus cases on Tuesday aboard the aircraft carrier USS Theodore Roosevelt, which is deployed in the Pacific.

These cases were the first aboard a deployed US warship, acting Navy Secretary Thomas Modly said at the Pentagon.

The number of infected sailors jumped to eight on Wednesday as five more sailors tested positive, a Navy official told Insider. On Thursday, the number of reported cases jumped to 25, with additional cases expected.

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More than a dozen sailors serving aboard the deployed US Navy aircraft carrier USS Theodore Roosevelt have the coronavirus, and more cases are expected in the coming days.

Acting Navy Secretary Thomas Modly announced Tuesday that "three cases of COVID-19 have been identified among personnel currently deployed and underway on the USS Theodore Roosevelt." He explained that "these are our first three cases of COVID-19 on a ship that is deployed."

The number of coronavirus cases on the aircraft carrier jumped to eight on Wednesday as five more sailors tested positive, a Navy official told Insider.

On Thursday, the Navy, without specifically mentioning the USS Theodore Roosevelt, reported that "17 Sailors assigned to a ship underway in the Pacific have also tested positive for COVID-19." A Navy official confirmed to CNN Thursday evening that at least 25 sailors have the virus.

There are roughly 5,000 Navy personnel aboard the Nimitz-class carrier, and the sailors on the ship live in close conditions in staterooms and berthing spaces.

The "Big Stick," as the carrier is nicknamed, is currently at port in Guam, where the Navy is testing the entire crew for the coronavirus. Sailors who test positive for the coronavirus are being quarantined and are being taken off the ship. Every person that the infected sailors had known contact with is also under quarantined.

While the first three cases marked the first time the coronavirus has been detected aboard a deployed warship, the Navy had already reported a number of cases among sailors assigned to pierside ships. As of Sunday, there had been at least a dozen cases among sailors aboard warships at port in San Diego.

US 7th Fleet said Saturday that members of Navy Forward Deployed Preventive Medicine Units and Naval Medical Research Center embarked aboard several ships in the Pacific.

Testing for COVID-19, the disease caused by the coronavirus, is being conducted aboard the amphibious assault ship USS America, the USS Theodore Roosevelt, and the 7th Fleet flagship USS Blue Ridge. The Navy said Tuesday that it is trying to increase testing, especially aboard its big-deck ships.

Update: This piece, which was first published March 24, has been updated with the latest numbers.