The move would help Trump get USD 5.6 billion for the construction of the wall that, he has asserted, is essential for national security.
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, White House Press Secretary Sarah Sanders said in a statement.
The President is once again delivering on his promise to build the wall, protect the border, and secure our great country, she said.
The White House statement came soon after Senate Majority leader Mitch McConnell made the move public.
I had an opportunity to speak with President Trump and he, I would say to all my colleagues, has indicated he's prepared to sign the bill. He also (will) be issuing a national emergency declaration at the same time. I indicated I'm going to support the national emergency declaration," McConnell said.
On the Democrats saying they will challenge the move in the Supreme Court, Sanders said, "We're very prepared, but there shouldn't be (legal challenges). The president's doing his job. The Congress should do theirs."
Senate Minority Leader Chuck Schumer and House Speaker Nancy Pelosi said that declaring a national emergency would be a lawless act, a gross abuse of the power of the presidency and a desperate attempt to distract from the fact that Trump broke his core promise to have Mexico pay for his wall."