'I am President, they're not': Trump rips media

US President Trump has ripped into the "fake media" during a speech at an evening rally in the capital to honour American veterans.

"The fake media tried to stop us from going to the White House, but I'm President and they're not. We won, and they lost," Trump said during the Celebrate Freedom Rally at the Kennedy Center in Washington D.C. on Saturday.

"The dishonest media will never keep us from accomplishing our objections on behalf of our great American people. It will never happen. Their agenda is not your agenda, you've been saying it," he said.

Trump also said the media have "destroyed themselves" by going too far: "Instead of being subtle and smart, they used the hatchet, and the people saw it right from the beginning", ABC News reported.

The President continued his attack on Joe Scarborough and Mika Brzezinski, the hosts of MSNBC's "Morning Joe", two days after saying on Twitter that Brzezinski had been "bleeding badly from a face-lift" during a social event last year.

Before taking off from Bedminster, New Jersey, to travel to the event in Washington, Trump tweeted in defence of his use of the social media.

"My use of social media is not Presidential -- it's MODERN DAY PRESIDENTIAL. Make America Great Again!" he tweeted.

On Saturday, he added: "Crazy Joe Scarborough and dumb as a rock Mika are not bad people, but their low rated show is dominated by their NBC bosses. Too bad!"

Trump also continued his blistering criticism of CNN in a series of tweets.