WASHINGTON (AP) — The Trump administration has awarded more contracts to build prototypes for the wall President Donald Trump wants to build on the U.S. border with Mexico.

WASHINGTON (AP) — The Trump administration has awarded more contracts to build prototypes for the wall President Donald Trump wants to build on the U.S. border with Mexico.

The prototypes announced Thursday by U.S. Customs and Border Protection are for four see-through walls. Last week, it announced contracts for prototypes for four concrete walls.

The eight prototypes will cost a total of $3.6 million and will be built in San Diego, probably during this fall.

The wall was a signature issue in Trump's campaign last year. He promised that Mexico would pay for it, but Mexico has refused. He is pushing Congress to fund it, but faces strong opposition from Democrats.