'Only wall will end shutdown' - Trump

In a Christmas Day appearance in the Oval Office, Mr Trump issued a lengthy defence of his desire for a wall, saying it is the only way to stop drugs and human traffickers from entering the US.

In a nod to the political stakes he's facing, the president said he wants the wall by "election time" in 2020.

Promise

The promise of a border wall was a central component of Mr Trump's presidential campaign.

"I can't tell you when the government's going to be open. I can tell you it's not going to be open until we have a wall or fence, whatever they'd like to call it," Mr Trump said, referring to Democrats who staunchly oppose walling off the Mexican border.

"I'll call it whatever they want, but it's all the same thing."

He argued that drug flows and human trafficking can only be stopped by a wall.

"We can't do it without a barrier. We can't do it without a wall," Mr Trump said.

"The only way you're going to do it is to have a physical barrier, meaning a wall. If you don't have that then we're just not opening [the government]."

Democrats oppose spending money on a wall, preferring instead to pump dollars into fencing, technology and other means of controlling access to the border.

Mr Trump argued that Democrats oppose a wall only because he is for one.

The stalemate over how much to spend and how to spend it caused the partial government shutdown, which began on Saturday following a lapse in funding for departments and agencies that make up about 25pc of the US government.

Some 800,000 government workers are affected. Many are still working but must wait until after the shutdown to be paid again.