Donald Trump is set to call in the National Guard to Washington DC in a bid to smash the US capital's crime and homelessness crises.

Hundreds of troops will soon flood DC, according to an American official - a tactic Trump last used to halt furious riots over immigration enforcement in Los Angeles.

The President has not made a final decision, the official added, and said the precise number of troops and their role are still up in the air.

But it comes just hours after Trump vowed to "beautify" his nation's capital.

"I'm going to make our Capital safer and more beautiful than it ever was before," he said on Truth Social.

"The homeless have to move out, IMMEDIATELY. We will give you places to stay, but far from the capital."

The President also rattled off a shot at the offenders which he has accused of plunging Washington into a crime crisis.

"The criminals... you don't have to move out. We're going to put you in jail where you belong. It's all going to happen very fast, just like the border.

"We went from millions pouring in, to zero in the last few months. This will be easier - be prepared! There will be no 'MR NICE GUY'.

"We want our capital BACK. Thank you for your attention to this matter!"

Teasing a press conference set to follow on Monday, the President later said: "It will not only involve ending the crime, murder, and death in our nation's capital, but will also be about cleanliness and the general physical renovation and condition of our once beautiful and well maintained capital."