The border fence is the largest and most expensive undertaking by the U.S. Department of Homeland Security, which took over border security responsibilities when it was created in 2002, the Fort Worth (Texas) Star-Telegram reported Sunday.

Tetra Tech, a California company, helped build the border wall near San Diego. It is close to completing a $12 million, 3.4-mile section near the Santa Teresa Point of Entry in New Mexico.

The project includes 53 miles of fencing designed to impede foot and vehicular traffic in the Border Patrol's El Paso sector, which includes all of New Mexico and two counties in western Texas.

Joe Romero, a U.S. Border Patrol agent in El Paso, said the fence will help agents gain a valuable advantage as they pursue immigrants sneaking into the United States or suspected criminals fleeing into Mexico.

"Five seconds can mean the difference between apprehending somebody or having them get away," he said. "This area used to be notorious for a lot of human, as well as narcotic, smuggling, and we've seen quite a dramatic decline."