BOULEVARD - Seven suspected illegal immigrants were injured in rural San Diego County early Thursday when their car slammed into a tree during a Border Patrol chase.

The crash occurred about 4 a.m. on Old Highway 80, about two miles from Boulevard, an unincorporated community east of San Diego, Border Patrol spokesman Richard Smith said.

Smith said agents in a marked car started the pursuit after spotting a 1991 Cadillac De Ville carrying suspected illegal immigrants.

California Highway Patrol spokesman Brian Pennings said the car was traveling about 70 mph when it went off the highway at a junction and smashed into a large oak tree. The speed limit in the area is 55 mph.

Five men and two women were injured. Three of the group were in the trunk at the time of the crash.

All were taken to local hospitals for treatment of various wounds.

Pennings said it appeared that all seven were undocumented Mexican nationals. He identified the man in the front passenger seat as Salvador Zepeda, 33. He suffered a broken leg and cuts to his face.

The driver, suspected of being the smuggler, fled the scene on foot and was not found during a two-hour search, Smith said.

The CHP was investigating the cause of the crash.