President Trump is asking Congress to approve $18 billion in funding to finance his proposed wall along the U.S.-Mexico border, CBS News confirmed Friday.

The request, which was first reported by The Wall Street Journal and confirmed to CBS News by a White House official, would cover construction of the wall over a decade. The official said that it's a potential ask for lawmakers as they craft border enforcement measures and will be discussed at a Camp David retreat this weekend attended by Mr. Trump, GOP congressional leaders and members of the Cabinet.

An administration official said that the document from the Department of Homeland Security that features the $18 billion request only covers one aspect of Mr. Trump's immigration priorities and was delivered to Capitol Hill to meet a specific request from negotiating team members.

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The WSJ report said that the $18 billion would go toward 700 miles of new replacement barriers, expanding the current 654 miles of barrier to nearly 1,000 miles. It's unclear if this funding would be part of any governmentwide spending package that's currently being negotiated in Congress.

House Minority Leader Nancy Pelosi, D-California, reacted to the report in a letter to House Democrats Friday, "This is alarming. We must all speak out."

In recent days, Mr. Trump has said that any legislative deal to protect so-called "Dreamers" and make the Deferred Action for Childhood Arrivals (DACA) program permanent must "secure the wall." The president tweeted last Friday: "The Democrats have been told, and fully understand, that there can be no DACA without the desperately needed WALL at the Southern Border and an END to the horrible Chain Migration & ridiculous Lottery System of Immigration etc." He added: "We must protect our Country at all cost!"

Prototypes for the border wall were completed in October and U.S. Customs and Border Protection (CBP) said at the time that it would soon begin testing them. The administration may be preparing for the wall, but Congress has not allocated funding for it. Funding has been repeatedly blocked by Democrats whose votes Republicans need for spending bills in the Senate. Spending legislation requires 60 votes to advance in the upper chamber and Republicans only have 52 members.

If the president fails to deliver on the border wall, that could hurt Republican candidates in November. On the other hand, if Dreamers don't receive further protections, that could also alienate Hispanic voters and hurt GOP election chances as well.

CBS News' Margaret Brennan and Katie Ross Dominick contributed to this report.