A leading contender in the race for Democratic chair has claimed Donald Trump 'legitimately raises the question of impeachment'.

Rep. Keith Ellison, the Muslim congressman from Minnesota who the president gave a backhanded compliment to on Wednesday, said he'd done 'a number of things' which warrant investigation.

'I think that Donald Trump has already done a number of things which legitimately raise the question of impeachment.

'On day 1, he was in violation of the emoluments clause. This is a part of the constitution which says as president, you can't get payments from a foreign power.

'The day people checked in to his hotel and started paying him, foreign dignitaries, he was in violation of that law,' Ellison said at a debate between candidates for the chairmanship on Wednesday.

'Right now it's not only about Donald Trump, it is about the integrity of the presidency.

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Rep. Keith Ellison said on Wednesday he agreed with Democrats who want to see Trump impeached, telling a debate for the leadership of his party that the president had done 'a number of things' to raise the question

'So yeah, I think that we need to begin investigations to not go after Donald Trump but to protect our Constitution and the presidency of the United States to make sure that nobody can monetize the presidency and make profit off of it for their own gain,' he continued.

Ellison had been asked by CNN's Chief Political Correspondent Dana Bash, who was moderating the Atlanta debate, whether he stood with fellow Democrats calling for Trump to face impeachment.

His bold comments came hours after the president delivered him a backhanded compliment on Twitter.

Ellison said the president should be investigated for possibly 'monetizing' the presidency

'One thing I will say about Rep. Keith Ellison, in his fight to lead the DNC, is that he was the one who predicted early that I would win!' he said.

Ellison was laughed at in 2015 during an on-air interview with ABC's George Stephanopoulos and New York Times reporter Maggie Haberman for his prediction.

It came days after Trump announced his campaign and Ellison said it ought to be taken seriously by voters.

'Anybody from the Democratic side of the fence who thinks that – who is terrified of the possibility of President Trump – better vote, better get active, better get involved because this man has got some momentum, and we'd better be ready for the fact that he may be leading the Republican ticket,' he said on a Sunday morning broadcast of ABC's 'This Week.'

'I know you don't believe that,' responded Stephanopoulos while Haberman apologized for laughing.

'You know, George, we had Jesse Ventura win the governorship in Minnesota. Nobody thought he was going to win. I'm telling you, stranger things have happened,' Ellison replied snappily.

Democrats in Washington are playing down talks the president should face impeachment over his ties to Russia, insisting that more investigations ought to be carried out before any action is taken to remove Trump from office.

Trump earlier praised the congressman, telling Twitter followers how he'd been one of the first to predict his election win

Ellison, a Bernie Sanders favorite, is a front-runner in the race for the new chair of the Democratic National Committee

Ellison said Trump had violated the constitution if he'd accepted money from foreign dignitaries by having them stay at Trump International Hotel (above)

Minority leader Nancy Pelosi said earlier this month any talk of the 'I word' - as it has become known - is premature.

'[There] are grounds for displeasure and unease in the public about the performance of this president who has acted in a way that is strategically incoherent, that is incompetent and that is reckless. And that is not grounds for impeachment,' she said.

California Rep. Eric Swalwell echoed her comments, telling Politico: 'We need to assemble all of the facts, and right now there are a lot of questions about the president’s personal, financial and political ties with the Russian government before the election, but also whether there were any assurances made.'

Pennsylvania Rep. Brendan Boyle chimed in: 'The ‘I’ word we should be focused on is "investigations."'

Talk of impeachment had begun even before the inauguration when far-left California Rep. Maxine Walters said the then incoming president could face impeachment if it could be proven he colluded with Russian meddling in the election.

'If we discover that Donald Trump or his advocates played a role in helping to devise strategy – if they're the ones who came up with "Crooked Hillary," if they’re the ones who came up with, "She's ill, something’s wrong with her energy," and the way that he basically described her during the campaign – I think that is something that would put the question squarely on the table, whether or not he should be impeached,' she told MSNBC.