The latest estimate for how much it would cost to build a wall along the U.S.-Mexico border has shot up far beyond what President Donald Trump has said it would cost.
According to an internal report by the U.S. Department of Homeland Security, the new estimated cost is $21.6 billion and it would take 3 1/2 years to complete the wall, reported Reuters. That's almost twice as much as the $12 billion price tag Trump touted during his presidential campaign.
Around 654 miles of the U.S.-Mexico border already have walls or fences. The DHS estimate represents the cost to build another 1,250 miles by the end of 2020.
According to the report, the first phase would cost $360 million and begin in places where there are already large sections of border walls, including San Diego, California, and El Paso, Texas.
This would allow Trump to score a political win by showing supporters he's serious about building a wall between the U.S. and Mexico, Reuters notes.
But while that particular phase of the project would only cost $360 million, getting congressional approval for another $21 billion might prove difficult because even some Republicans are against the idea.
"If you're going to spend that kind of money, you're going to have to show me where you're going to get that money," said Republican Sen. Lisa Murkowski of Alaska, according to CNN. "I don't see how you can get a bill like that through [Congress] without offsets. I don't see how that's possible."
"I have concerns about spending un-offset money, which adds to the debt, period," said Republican Sen. Jon Cornyn of Texas. "I don't think we're just going to be able to solve border security with a physical barrier because people can come under, around it and through it."
And the real cost of the wall might be even higher.
According to the MIT Technology Review, the cost of building, maintaining and securing the wall could add up to $40 billion.