Watch: Trump spars with Democrats over US-Mexico border wall

US President Donald Trump openly fought with the top two Democratic lawmakers at an Oval Office meeting on Tuesday about government funding, throwing into question whether a deal was possible ahead of a deadline later this month.

In a remarkable public argument, the likes of which is seldom seen before cameras, Trump bickered with US Senate Democratic Leader Chuck Schumer and House Democratic Leader Nancy Pelosi about funding for his border wall.

The president has called for $5 billion to fund the barrier along the US-Mexico border, a campaign promise that he has made into a central issue. He ended the argument by saying he was willing to make good on his repeated threat to shut down the federal government over the issue.

"It's called transparency," Trump said after Pelosi protested about the public nature of the spat.

Congress is seeking to finalize spending before some federal government funding expires on December 21. While Trump's fellow Republicans control both the House and the Senate until next month, Democratic support is needed to pass any spending legislation.

It was unclear how Trump would try to use the US Department of Defense to build the wall, given that defence and military construction appropriation bills were signed into law for the 2019 fiscal year without any wall funding.