US President Donald Trump has issued an executive order to build the Mexico border wall and has suggested that the construction will begin "in months".

The Republican signed the order on Wednesday (25 January). In an interview with ABC News, Trump said planning would begin immediately and construction would follow shortly afterwards.

As he signed the order, also inking an action that will remove funds from "sanctuary cities" that protect undocumented immigrants, he said: "We've been talking about this right from the beginning," the BBC reported.

"As soon as we can, as soon as we can physically do it," he said in response to a question about when construction would begin.

"I would say in months, yeah. I would say in months, certainly planning is starting immediately.

"All it is, is we'll be reimbursed at a later date from whatever transaction we make from Mexico," he added.

"I'm just telling you there will be a payment. It will be in a form, perhaps a complicated form. What I'm doing is good for the United States. It's also going to be good for Mexico. We want to have a very stable, very solid Mexico."

According to the Associated Press (AP), Mexican President Enrique Pena Nieto is considering cancelling his trip to Washington DC on Tuesday (31 January) following the executive order.

Trump's announcement that construction of the wall will begin imminently has prompted heated debate over payment – with one GOP lawmaker proposing "creative solutions".

House Homeland Security Committee Chairman Michael McCaul suggested charging a "border security fee" on visa applications from Mexico and Central American countries to cover the cost of building the controversial wall.

The countries liable for the undetermined fee would be those perceived to be sources of illegal immigration into the US, although McCaul suggested – as Trump had previously indicated – the initial cost would be funded by taxpayer dollars.

McCaul said in an interview with Bloomberg: "I think there are some creative ideas that I've been coming up with and others in the Congress where the taxpayer makes the initial down payment, but then eventually the security measures pay for it by things like increasing the – putting a border security fee on visa applications from Mexico and Central American countries that are the biggest offenders of illegal immigration."