More than 5,000 personnel on board the ship have been quarantined. (Representational image)

Three US sailors from the aircraft carrier USS Theodore Roosevelt have been diagnosed with the novel coronavirus, the first cases reported on a US Navy ship currently on deployment, officials said on Tuesday.

The three have been evacuated and all those they had come into contact with on the vessel, which has more than 5,000 personnel on board, have been quarantined, Acting Navy Secretary Thomas B. Modly told reporters.

The ship was last in port in Vietnam 15 days ago but Chief of Naval Operations Admiral Mike Gilday said it was difficult to connect the cases to a particular port visit.

“We took great precautions when the crew came back from that shore visit, and did enhanced medical screenings of the crew,” he said. Overall, the Navy has 86 coronavirus cases, including 57 active-duty service members, he said.

Last week the amphibious assault ship USS Boxer — currently in port in San Diego according to US media — reported one of its personnel had tested “presumptive positive” for the virus.