Watch live: President Trump visits southern border of U.S.

President Trump on Thursday will visit the southern border of the United States as he continues to promote building a wall between the U.S. and Mexico — a signature promise of his 2016 presidential campaign.

Trump’s demand for $5 billion in funding for a wall at the border is at the center of an impasse between Trump and Democratic lawmakers that spurred the ongoing, partial government shutdown that began on Dec. 22.

In a televised address, the president on Tuesday pleaded his case to the American public, saying, “This is a humanitarian crisis.” Democratic leaders House Speaker Nancy Pelosi and Sen. Minority Leader Chuck Schumer thereafter issued a joint rebuttal arguing for the president to sign a spending bill that would re-open the federal government without border wall funding.

The president has floated the possibility of declaring a national emergency to enable a unilateral decision on the border wall.