UPDATE 1:48 p.m.:
The order to begin construction on the wall has already been signed, Reuters reports.
Trump also signed an executive order removing federal funding for "sanctuary cities," which don't arrest or detain undocumented immigrants living in the U.S. illegally.
President Trump said construction of the Mexican border wall, for which he is expected to sign an executive order Wednesday afternoon, will begin within "months."
Trump, in an ABC News interview aired Wednesday, said Mexico would "reimburse" the U.S. for the wall.
"It will be in a form, perhaps a complicated form," Trump said in his first one-on-one interview since being sworn in as president.
WATCH | Here's a clip of the interview.
As soon as we can, as soon as we can physically do it.
Trump said the wall would be good for the U.S. and "It's also going to be good for Mexico. We want to have a very stable, very solid Mexico."
This comes after a Mexican delegation came to discuss the wall with senior White House officials, bringing a "Mexico First" position, CNN reports.
"There is a lot of anger that we have become this punching bag," a senior Mexican diplomat told CNN.
Back in July, Mexican President Enrique Peña Nieto insisted there was "no way" Mexico would pay for the wall.
Critics seemed doubtful Mexico would reimburse the U.S.
Others said a wall might be physically impossible.
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