Eleven people were hurt, with seven hospitalized, when a Metro bus collided with a parked semitruck in South El Monte early Wednesday morning, fire officials said.

One of them was a 57-year-old man who was critically injured in the head and taken to Los Angeles General Medical Center, sheriff’s Sgt. Robert Leyba said. The rest had minor injures or complained of pain.

The bus driver was among the injured.

The collision was reported shortly after 6 a.m.

The bus was heading north on Rosemead Boulevard when it hit the semitruck loaded with lumber that was parked, according to a sheriff’s statement. The semitruck was on Rosemead between Klingerman and Rush streets.

Deputies don’t yet know why the bus struck the parked truck.

It wasn’t clear how many passengers were on the bus.

The bus, part of Line 266, is operated by Southland Transit, a contractor for L.A. Metro.

Deputies asked anyone with information about the collision to call them at 626-285-7171. Anonymous tipsters can call Crime Stoppers at 800-222-8477 or go to lacrimestoppers.org.