SAN DIEGO (CBS 8/CNS) - A person was killed on Interstate 5, near the US-Mexican border in San Ysidro early Saturday.

It occurred at 2:25 a.m. on the freeway's southbound lanes, just north of the US Port of Entry, according to the California Highway Patrol.

The CHP shut down some lanes on the freeway for more than three hours as officers investigated.

The cause of the crash is unknown, officials said.

The motorist was pronounced dead at the scene.