The Department of Homeland Security will begin building border wall prototypes this summer in San Diego, the agency told reporters Tuesday.

Ronald Vitiello, acting deputy commissioner at Customs and Border Protection, said the agency would build four to eight prototypes to add to existing border walls. It will then evaluate what kind of barrier is most effective in combating drug and human smuggling.

"We own that land, have access to it and it's a good place to start testing in a real-world environment," Vitiello said at a news briefing.

President Trump issued an executive order to build a border wall in January. Since then, Customs and Border Protection has issued two requests for proposals, for both a concrete wall and other wall types, the New York Times reported.

The agency has received hundreds of bids, but hasn't yet chosen vendors.

Immigration officials are using $20 million from other programs to pay for the prototypes. The Republican-controlled Congress did not provide new money for a border wall in a spending bill it passed in May, instead giving money for technology at the border.

Lawmakers in both parties, especially those representing border states and districts, have questioned whether a wall is the best approach to securing the border, noting the cost and complications in securing rights to land to build on.