Construction could begin within "months" according to Trump.

Donald Trump has signed an executive order to the Department of Homeland Security which calls for a "large physical barrier" between the US and Mexico. His Press Secretary Sean Spicer told reporters on Wednesday: "The first order will kickstart the building of “a large physical barrier on the southern border”. “Building this barrier is more than just a campaign promise. It’s a common sense first step to really securing our porous border. This will stem the flow of drugs, crime, illegal immigration into the United States.” Today, Trump signed two executive orders during a visit to DHS headquarters, that would direct the organisation to build the wall, increase the number of border patrol agents and increase the deportation of immigrants. "As soon as we can, as soon as we can physically [build] it," Donald Trump told ABC News. "I would say in months, yeah. I would say in months, certainly planning is starting immediately." While he admitted that taxpayers would initially have to foot the bill for the order, he claimed that they would be reimbursed by Mexico "100%" at a later date. "I'm just telling you there will be a payment," Trump said. "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."