SAN DIEGO -- A Border Patrol pursuit turned deadly when a pickup truck packed with suspected illegal immigrants crashed into a freeway bridge support in Descanso, killing two people and leaving at least a dozen others injured.

The wreck occurred about 4:15 p.m. Thursday on westbound Interstate 8 at state Route 79, ending a 22-mile chase by Border Patrol agents, said Guy Impastato of the San Diego Fire Department.

The accident left the pickup crumpled against a guardrail and people sprawled around it, on the roadside and down a bank adjacent the east-west thoroughfare below.

Two people were killed in the crash and, seven others were in critical condition, including a young boy. One person was said to have moderate injuries, and five others had minor injuries, Impastato said.

The victims were airlifted to several local hospitals, he said.

At least 13 suspected undocumented immigrants were in the vehicle, most of them covered by a tarp in the back, said California Highway Patrol Officer Larry Landeros.

The pursuit began when Border Patrol agents tried to stop the truck near the U.S.-Mexico border near Tecate, Mexico.

The driver sped away and was followed by Border Patrol agents, Border Patrol spokesman Raleigh Leonard told the San Diego Union-Tribune.

Two attempts to stop the pickup using spike strips were unsuccessful, Leonard said.

Leonard said said that during the first two attempts to stop the truck, the driver attempted to run down Border Patrol agents.

A third attempt punctured a rear tire, but the vehicle kept going -- veering back and forth across the freeway -- at speeds estimated at 80 mph before the driver lost control and the pickup slammed into the bridge support, Leonard said.