Trump has not ruled out using his authority to declare a national emergency and direct the Defense Department to construct a border wall as Congress and the White House fight over a deal to end the government shutdown. But while Trump's advisers remain divided on the issue, the White House has been moving forward with alternative plans that would bypass Congress.

"The massive amount of aliens who unlawfully enter the United States each day is a direct threat to the safety and security of our nation and constitutes a national emergency," a draft of a presidential proclamation reads.

"Now, therefore, I, Donald J. Trump, by the authority vested in me by the Constitution and the laws of the United States of America, including the National Emergencies Act (50 U.S.C 1601, et seq.), hereby declare that a national emergency exists at the southern border of the United States," the draft adds.

The draft was updated as recently as last week, a US government official told CNN. -CNN