President Trump will declare a national emergency this week to build more border wall on the southern U.S. border, Majority Leader Mitch McConnell, R-Ky., announced from the floor Thursday.

McConnell said Trump would declare the emergency as he signs a border security compromise bill that Congress is expected to pass Thursday night. That bill lets Trump spend $1.375 billion on border fencing, but Trump has said for weeks he may declare an emergency if Congress doesn't give him the $5.7 billion he was looking for.

"He will also be issuing a national emergency declaration at the same time, and I've indicated to him that I'm going to ... support the national emergency declaration," McConnell said on the Senate floor. McConnell added he told Trump he supports his use of a National Emergency Declaration to win more border barriers.

The White House confirmed McConnell's understanding shortly after he spoke.

"President Trump will sign the government funding bill, and as he has stated before, he will also take other executive action — including a national emergency — to ensure we stop the national security and humanitarian crisis at the border," said press secretary Sarah Sanders. "The president is once again delivering on his promise to build the wall, protect the border, and secure our great country."

The House and Senate are scheduled to clear the spending bill today. Trump has indicated this week he will sign the bill even though it falls short of the money he wants, because he believes he has the authority to use pre-existing funding to build more border wall.

Democrats and some Republicans do not back the president's idea of using his executive authority to reallocate funding. Many Republicans said they want more information about how it would be accomplished.