The novel corona virus was diagnosed in three US sailors of the aircraft carrier USS Theodore Roosevelt. The first cases were reported on a U.S. Navy ship currently in service.
The three were evacuated and all those they encountered on the ship, which has more than 5,000 employees on board, were quarantined, Acting Marine Secretary Thomas B. Modly told reporters.
The ship was the last in port in Vietnam 15 days ago, but Admiral Mike Gilday, chief of naval operations, said it was difficult to relate the cases to a particular port visit.
"We took great precautions when the crew came back from this land visit and improved the medical examination of the crew," he said. In total, the Navy has 86 coronavirus cases, including 57 active duty members, he said.
Last week, the amphibious assault ship USS Boxer, which according to the US media is currently in the port of San Diego, reported that one of its employees had "presumably tested positive" for the virus.