When asked how soon it would be before he declare an emergency, the president said "if we don't make a deal with Congress most likely I will do that". Despite the fact any such move would bring legal challenges, Mr Trump said the law is "100 per cent on my side".
He went on to call the situation at the border "a national emergency, if you look what's happening."
Mr Trump did not lay out a specific timetable for when he might take the step of a declaration, saying: “I think we're going to see what happens over the next few days.”
Critics have accused Mr Trump of "manufacturing" a border crisis to try and get the wall as part of a deal to end a partial government shutdown.
Two days after delivering a televised address to the nation to make his case for a wall, and a day after he abruptly left a meeting with Democrats after they refused to pay for one, Mr Trump travelled to the city of McAllen where he signed autographs for supporters and met border agency officials.
At a roundtable meeting with community leaders and officials in McAllen, among them Texas senator Ted Cruz, the president repeated his insistence that a wall would be be built.
“We’re going to build a powerful steel barrier. They said we don’t want a concrete wall. I said that’s okay, we’ll call it a steel barrier,” he said.
“They say this is a manufactured crisis. That’s their new sound bite ... Every network has ‘manufactured crisis’. But it’s not. What’s manufactured is the word ‘manufactured’.”
The president - who has cancelled an upcoming trip to Davos, Switzerland, because of the shutdown - also sought to address those critics who have pointed out he used to repeatedly promise Mexico would pay for any barrier. He claimed without evidence that the terms of a new trade deal with Mexico and Canada will provide the money for the wall.
“When I say Mexico’s going to pay for the wall ... I didn’t say they’re going to write me a check for $10bn or $20bn,” he said. “If Congress approves this trade bill, they’ll pay for the wall many times over. When I say Mexico’s going to lpay for the wall, that’s what I mean”.
To see how events unfolded throughout the day, see our liveblog below
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