US President Donald Trump has angrily declared he doesn’t “do cover-ups” at a spontaneous media conference held after he stormed out of a meeting with Democratic politicians.

Mr Trump’s furious salvo came in reply to US House Speaker Nancy Pelosi’s accusations that he is engaged in a cover-up over the Mueller Russia investigation.

Visibly angered by Ms Pelosi’s remarks, Mr Trump also told reporters at the hastily arranged White House appearance that he would not work with Democrats on a major infrastructure proposal because of “phony” investigations they are pursuing in Congress.

According to US media reports, Mr Trump walked into the infrastructure meeting with Ms Pelosi and Senate Democratic Leader Chuck Schumer and refused not to shake either’s hand or sit down.

The President reportedly upbraided Ms Pelosi for her “terrible” allegation about a cover-up, demanded Democrats end their investigations against him, then abruptly left the room.

The meeting lasted less than five minutes.

Mr Trump said he was upset that Democratic lawmakers discussed the possibility of impeaching him before a White House meeting on infrastructure.

He also repeated his previous comments about Special Counsel Robert Mueller’s probe of Russia’s interference in the 2016 US presidential election and whether he impeded Mueller’s inquiry.

“No collusion, no obstruction, no nothing,” Mr Trump said. “This whole thing was a take-down attempt at the president of the United States.”

Regarding the infrastructure meeting, Mr Trump said he told Democrats he had wanted to focus on infrastructure.

“I walked into the room and I told Senator Schumer, Speaker Pelosi, I want to do infrastructure. I want to do it more than you want to do it. I’d be really good at that – that’s what I do. But you know what? You can’t do it under these circumstances. So get these phony investigations over with.”

At a later press conference with Mr Schumer, Ms Pelosi told reporters Mr Trump may have lacked the confidence to work with Democrats on infrastructure. She said she prays for Mr Trump.

“He just took a pass. And it just makes me wonder why he did that,” she said.

“I pray for the President of the United States. And I pray for the United States of America.”

During the press conference Pelosi said, “I pray for the President and I pray for the United States of America.” Photo: Getty

Mr Schumer said watching what happened at the meeting between the President and Democratic lawmakers “would make your jaw drop”.

He said that when Mr Trump was asked how he would pay for an infrastructure plan “he had to run away”.

As Democrats in Congress debated impeaching Mr Trump, Ms Pelosi said on Wednesday, about an hour before a White House meeting with him, that Mr Trump is engaged in a “cover-up”.

The President is stonewalling multiple congressional investigations by ignoring subpoenas, refusing to allow current and former advisers to testify, and not handing over documents, steps that have aggravated a confrontation with Congress.

“No one is above the law, including the president of the United States. And we believe that the president of the United States is engaged in a cover-up,” Ms Pelosi told reporters after a morning meeting of House Democrats.

Mr Trump and Democrats who control the House are engaged in a high-stakes power struggle over their ability to investigate him, with the president increasingly asserting that his advisers need not respond to lawmakers’ inquiries.

-with AAP