Donald Trump said he could step into an internal US Navy dispute about a fired aircraft carrier commander who was fired by the service's top civilian official for raising concerns about coronavirus spreading through his crew.

"I don't want to destroy somebody for having a bad day," the commander in chief said of Captain Brett Crozier.

Acting Navy Secretary Thomas Modly fired the commander of the aircraft carrier Theodore Roosevelt after a letter he wrote about the virus infecting his crew leaked to the San Francisco Chronicle.

Mr Modly on Monday said the letters show Mr Crozier was too "stupid" to command such a massive war ship.

The president declined to comment on that, other than saying it was a "strong statement."