WASHINGTON (AFP) - Donald Trump and Democratic congressional leaders rowed at the White House on Tuesday (Dec 11) over the president's threat to stop funding the US government if he doesn't get money for a Mexico border wall.

"If we don't get what we want, I'll shut down the government," Trump said during a heated exchange. "I will be the one to shut it down."

He spoke at a meeting with Chuck Schumer, the senior Democrat in the Republican-dominated Senate, and Nancy Pelosi, who is likely to become speaker in the newly Democrat-controlled House in January.

Trump wants Congress to agree to US$5 billion (S$6.9 billion) he says is needed to fund a large barrier along hundreds of miles of the US-Mexican frontier, but Democrats are willing to agree to far less, with emphasis on border security rather than an actual wall.

Trump has repeatedly threatened to shut down much of the government if Democrats do not back his plan. Swaths of federal funding will expire on Dec 21, forcing a partial government closing, unless a deal can be reached.

Tweeting ahead of the meeting with the opposition leaders, Trump claimed that the wall was needed to prevent "large scale crime and disease" brought by illegal immigrants.

"If the Democrats do not give us the votes to secure our Country, the Military will build the remaining sections of the Wall. They know how important it is!" he tweeted.

Opponents say the wall, arguably Trump's main campaign promise in his 2016 election, is not only a waste of money but has been used by the president to whip up xenophobia.

Washington has been paralysed by political gridlock for most of Trump's two years in office and the partisan divide is set to intensify in January when Democrats take over the majority in the lower house of Congress.

The power shift comes as Trump faces ever growing peril from criminal investigations, with talk growing of possible impeachment proceedings against the president.