WASHINGTON - A tractor-trailer and a school bus collided Wednesday in the western part of US state Pennsylvania, at least 15 were injured. There were also unconfirmed reports of death.

According to the Somerset Daily-American newspaper's website, the accident took place at about 2:45 pm on Route 281 near the Rockwood school bus garage about 15 miles south of Somerset. The area is about 70 miles southeast of Pittsburgh.

Six medical helicopters and numerous ambulances and fire departments are responding. A coroner was dispatched to the site of the accident, state police said, according to local CBS affiliate WPXI.

Local KDKA Pittsburgh said the school bus was taking students from the Turkeyfoot Valley Area School District to a vocational and technical school in Somerset.

Television footage suggests the front of the vehicles collided on a rural highway. The main body of the bus appeared to be intact.

Rhonda Hoover, secretary to the superintendent of the Turkeyfoot Area School District, was quoted by WPXI as saying that the injured students had been taken to Somerset Hospital.

Greg Chiappelli, a spokesman for Somerset Hospital, was quoted as saying eight people arrived by ambulance and another seven to 10 people with minor injuries were taken to the hospital by bus. He did not know the severity of the injuries.

The accident came one day after a school bus overturned in Missouri, injuring 11 students, and two days after a school bus crashed in Indiana killing the driver and one student.