Once built, they will undergo testing by the Department of Homeland Security.
And all the while, officials are preparing for a fair share of protests against the controversial project. The Los Angeles Times reports that miles of fencing have been put up in San Diego's Otay Mesa region — a "checkerboard of public and private land ownership" where the prototypes are to be built — and no-parking zones will be in effect through Nov. 10.
The free speech area designated for potential protesters is a "dusty, unshaded, weed-choked lot overlooking Otay Mesa and more than 1.5 miles away from construction," according to the San Diego Union-Tribune.
That said, the paper reports there appeared to be no protesters around as construction kicked off Tuesday, and at least one local activist expressed skepticism the project was even worth protesting at the moment.
"It's just political theater," Hiram Soto, spokesman for Alliance San Diego, told the Times. "There is no funding for it in Congress."
Trump relented earlier this month on a threat to shut down the federal government if lawmakers failed to approve funds for the wall, striking a deal with Democrats to delay multiple fiscal deadlines with no strings attached. He has also appeared to acknowledge he won't require border wall funding to be part of a possible deal to save the Deferred Action for Childhood Arrivals program, or DACA.
On the campaign trail and early in his administration, Trump had said repeatedly that Mexico would pay for the wall's construction — a proposition that has also been repeatedly rejected by Mexican leaders.
Estimates for the cost of the border wall have ranged up to $38 billion. The Department of Homeland Security plans to pay for the construction of the prototypes, which cost up to $500,000 each, with funds reallocated internally from other programs.
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