DALY CITY, Calif. (AP) — A commuter bus smashed into 16 cars at a San Francisco Bay Area shopping center on Friday, injuring four people, one of them critically, authorities said.

Shortly before noon, the SamTrans bus smashed into the vehicles at a Target store parking lot at the Serramonte Center in Daly City, fire officials said.

SamTrans said at least four people, including one in critical condition, were transported to San Francisco General Hospital.

A witness told KNTV-TV that the bus was turning into the shopping center when the driver lost control and the bus jumped a curb and plowed through the parking lot.

News video showed shopping carts under the front end of the bus and damaged cars scattered around it.

The bus driver told authorities that the vehicle’s brakes failed before the crash, county Supervisor David Canepa told KGO-TV.

Other details of the crash weren’t immediately available.

In a statement, SamTrans said it was working with investigators from the Sheriff’s Office.

“As we work to gather information about the cause of this incident, our hearts go out to those affected,” the statement said.

The public agency provides bus service throughout San Mateo County and for portions of San Francisco and Palo Alto.