San Ysidro Border Shooting: U.S.-Mexico Border Crossing Closed

11/22/2009 04:12 am ET | Updated May 25, 2011

SAN DIEGO — Four people were injured in a gun battle Tuesday involving an attempt to smuggle illegal immigrants from Mexico at the busiest border crossing in the U.S., authorities said.

More than 70 people traveling in three vans involved in the incident were in federal custody, said U.S. Customs and Border Protection spokeswoman Angelica DeCima.

Details remained sketchy, but van drivers tried to storm past inspectors at the San Ysidro port of entry and make their way into the U.S. without stopping, DeCima said.

"It was human smuggling, definitely," said Lauren Mack, a spokeswoman for U.S. Immigration and Customs Enforcement.

Three of the injured people were in the vans, and a fourth was in another vehicle, DeCima said. It was unclear how serious the injuries were.

An ICE agent and a CBP officer fired their guns during the shootout, DeCima said.

The shootout occurred over nine lines of traffic in the 24 northbound lanes, said Monica Munoz, a San Diego police spokeswoman.

About 40,000 vehicles enter the U.S. each day at San Ysidro, which connects San Diego and Tijuana, Mexico. Investigators closed the port to vehicle traffic from Mexico to the United States.