Three US sailors aboard an aircraft carrier stationed in the Philippine Sea tested positive for coronavirus and were flown from the ship, according to a report.

Acting Navy Secretary Thomas Modly told reporters at the Pentagon on Tuesday that the sailors, who were aboard the USS Theodore Roosevelt, are the Navy’s first confirmed cases among personnel at sea, Stars and Stripes reports.

The sailors were flown to a military hospital in the Pacific region, Adm. Michael Gidlay, chief of naval operations, told Stars and Stripes.

There are about 5,000 people aboard the aircraft carrier and Gidlay did not say how many of them are being quarantined after coming in contact with the sailors.

The Roosevelt was in port in Saigon just over two weeks ago, though Gidlay did not draw a direct connection between the port call and the positive cases on the ship, the report states.

“Whenever we have a positive [test] on any ship with any unit … we’re doing the forensics on each one of those cases to try and understand what kind of best practices, or the do’s and the don’ts that we can quickly promulgate fleet-wide,” he said.

Vietnam had 16 confirmed COVID-19 cases at the time of the Roosevelt’s port call, but by Wednesday the count had grown to 141, according to the Vietnamese government.

The Navy has 86 active coronavirus cases, of whom 57 are service members, 13 are civilian workers, 11 are dependents and five are contractors, Modly said.

Also on Tuesday, the Navy reported that a sailor stationed at Guantanamo Bay, Cuba, tested positive for COVID-19.