WASHINGTON • US President Donald Trump warned evangelical leaders that if Republicans lose control of Congress in the midterm elections, Democrats will institute change "quickly and violently", the New York Times reported.

At a meeting with the leaders at the White House on Monday, Mr Trump said everything was at stake for his conservative agenda if his party loses in November's elections, according to an audiotape of the meeting obtained by the newspaper.

Democrats "will overturn everything that we've done and they'll do it quickly and violently", Mr Trump said, according to the Times report published on Tuesday night.

"They will end everything immediately," he stated.

"When you look at Antifa," the president added, referring to militant leftist anti-fascism groups, "and you look at some of these groups, these are violent people."

It was not the first time Mr Trump has warned of violence if things did not go his way.

During the 2016 presidential campaign, he said his supporters would probably react violently if he did not win the Republican nomination.

"I think you'd have riots," Mr Trump warned.

The Times said reporters were allowed to listen in on brief comments by Mr Trump during the Monday meeting with ministers and pastors, and heard him talk about abortion, religious freedom and youth unemployment.

But after the press was shown out of the room, Mr Trump changed the subject and suggested how the evangelical leaders could help Republicans win in November, the Times reported.

"I just ask you to go out and make sure all of your people vote," the president said.

"Because if they don't - it's Nov 6 - if they don't vote we're going to have a miserable two years and we're going to have, frankly, a very hard period of time because then it just gets to be one election - you're one election away from losing everything you've got."

AGENCE FRANCE-PRESSE