Homeland Security Secretary Kirstjen Nielsen is headed for a three-day tour of the country’s southern border, which President Trump last week threatened to close in an effort to stem the tide of illegal immigrants entering the US.

Nielsen will arrive Wednesday in El Paso, Texas, where she will be briefed by local US Customs and Border Patrol honchos on efforts to maintain order along the Mexican border, DHS announced.

On Thursday, Nielsen will head to Yuma, Arizona to sit in on a roundtable panel with DHS leadership, as well as local law-enforcement and elected officials.

Nielsen will wrap up the trip on Friday, when she will join Trump in Calexico, California for a second roundtable, as well as a review of a stretch of border wall outside the city, the agency said.

The visit comes less than a week after Trump threatened on Twitter to “close the Southern Border” in order to “stop the flow of illegal immigrants to our Country.”

Trump earlier this week was reportedly weighing the appointment of a border “czar” to combat what he has called a “crisis.”

Trump in February declared a national emergency to build a wall spanning the entirety of the border, a hallmark campaign promise long bogged down by his fight to secure congressional funding that came to a head with a protracted federal government shutdown.