BALTIMORE -- A nearly empty school bus crossed into oncoming traffic and slammed into a commuter bus in Baltimore on Tuesday morning, killing at least six people, police said.
The school bus, which was blocks away from its first pickup of the day, had no children on board at the time of the crash, Baltimore Police spokesman T.J. Smith said.
The crash, which injured at least 10 people, sheared the driver's side off the commuter bus, Smith said.
"It literally looks like a bomb exploded in the bus," he said. "It is catastrophic damage."
The school bus first hit a car, then went off the road into a cemetery and struck a pillar before returning to the roadway and colliding with the commuter bus, Smith said.
Video from WBAL shows the school bus wedged into the side of the commuter bus, with firefighters surrounding the scene.
The school bus driver and five people aboard the commuter bus were killed, Smith said. Rescuers transported 10 people to local hospitals with injuries. Investigators are working to pinpoint what caused the crash.
An aide who was on the school bus and survived the crash might be able to help investigators shed light on what happened, Smith said.
There were no skid marks in the road, Smith said, "so something catastrophic took place, and it's something we're continuing to investigate."