BRENDAN SMIALOWSKI/AFP/Getty

President Donald Trump will sign an order declaring a national emergency at the southern border with Mexico as he looks to find funding for the border wall he has promised to build since he was just a candidate for presiddent.

Trump, who made the announcement in the White House's Rose Garden on Friday, said that he will sign the order in the Oval Office as soon as his press conference was over. 

"Today we will be signing and registering for a national emergency. And it's the right thing to do," Trump said. "It's very very simple. We want to stop drugs from coming into our country. We want to stop gangs from coming into this country. Some people didn't step up, but we're stepping up now. But we are going to have close to $8 billion for the wall."

Trump said that he expects his order to face opposition in court as Democrats sue to stop him from declaring a national emergency.

Congress allocated $1.375 billion to build 55 new miles of steel fencing in a bipartisan deal struck Thursday that headed off another government shutdown that was scheduled to start Friday if a compromise wasn't reached. 

That $1.375 billion allocation is only a fraction of the $5.7 billion Trump requested to secure the southern border with a wall. 

With the national emergency order, Trump will be able to get the money needed for the wall from the Department of Defense budget. Trump touted the fact that he raised defense spending above $700 billion annually before saying that the budget could suffer the "$2 to $3 billion" extra he needs to build his wall. 

Trump also is expected to sign funding legislation Friday that would avoid another government shutdown.