WASHINGTON (Diya TV) — President Donald Trump on Wednesday issued an executive order for an “impassable physical barrier” to be built along the U.S.-Mexico border.

Additionally, President Trump signed an action to strip funds from the country’s “sanctuary cities,” or cities where undocumented immigrants can reside without fear of arrest or deportation.

Trump said, during an interview with ABC News, that Mexico would be “absolutely, 100 percent” reimbursing the American taxpayer for the wall’s construction. However, Congress would be required to approve funding for construction, which, by Trump’s own estimates, will cost more than $6 billion to construct. Building a 2,000-mile structure along the U.S.-Mexico border was one of the most vocal points of Trump’s presidential campaign.

The Government Accountability Office has estimated that it could cost $6.5 million per mile to build a single-layer fence, and an additional $4.2 million per mile for roads and more fencing, according to congressional officials. Those estimates do not include maintenance of the wall.

Speaking at the Department of Homeland Security Wednesday, President Trump spoke of a “crisis” on the southern U.S. border, and announced that 10,000 immigration officials would be hired to bolster efforts along the border.

“A nation without borders is not a nation,” he said. “Beginning today the United States gets back control of its borders.”

Trump is scheduled to meet with Mexican President Enrique Pena Nieto at the end of the month, and said U.S. relations with Mexico would get “better” after that point.

The freshly sworn-in president is expected to target illegal immigrants as early as this week, White House officials said, by halting a decades-old program that grants refuge to the world’s most vulnerable people as he begins the process of drastically curtailing it and enhancing screening procedures.