U.S. President Donald Trump has been transported to a military hospital after testing positive for the coronavirus.

Trump was seen at the White House boarding a helicopter headed to Walter Reed Army Medical Centre in Maryland on Friday, his first public appearance since he announced that he had tested positive for the virus in the early hours of Friday morning.

The president was wearing a mask and gave a thumbs up to reporters, but did not stop to answer questions. 

Reporters on the scene said that Trump walked normally and did not show any visible signs of sickness.

Citing two officials familiar with his condition, the Washington Post said Trump is struggling with a low-grade fever, a cough and nasal congestion, among other symptoms. 

One official said the president is not seriously ill but given his age and other risk factors, he has been transferred to Walter Reed. 

In a video message on Twitter, Trump said he is doing very well and thanked everyone for their tremendous support. 

Trump canceled a planned campaign event in Florida and had Vice President Mike Pence take over a planned conference call as well.