SAN FRANCISCO, Jan. 9 (Xinhua) -- Fifteen people were injured, two critically, in a collision Tuesday morning when a school bus crashed into two vehicles in El Sobrante in western U.S. state of California, local Fire Protection District said.

Confire PIO@ContraCostaFire tweeted that all the 15 wounded people have been transported to area hospitals, while three other people were released after being treated on scene.

The bus was carrying children from a special education school in Contra Costa County.

A pickup truck and a private car, which collided with the school bus, were damaged in the accident.