MORRISTOWN, New Jersey • A student and a teacher were killed and 43 others injured when a school bus with pre-teens on a field trip collided with a dump truck on a New Jersey highway.

The collision on Thursday morning in Mount Olive township in northern New Jersey's Morris County ripped the bus apart and left students dangling by their seat belts, according to officials.

The bus was carrying students from the East Brook Middle School in Paramus, west of upper Manhattan, to Waterloo Village - a restored 19th-century canal town, officials said. There were 38 students and seven adults on board, including the driver.

"Some patients are in critical condition and currently undergoing surgery, so please keep everybody in your prayers," Governor Phil Murphy told a news conference. "There is an awful lot we just don't know," he said, adding that details of the crash were not being released pending an investigation.

The front end of the bus was severed from the vehicle and the body was separated from its chassis, which remained on the highway. The dump truck seemed to be mostly intact.

"The bus flew off of the wheels, but it hit the metal thing on the side of the highway," fifth-grader Theo Ancevski said. He told reporters he escaped through an emergency door. US fifth-graders are generally aged 10 or 11.

"The children were all over, outside," said Morris County Office Of Emergency Management Director Jeff Paul. "It's tragic," he said.

The operator of the dump truck, Mendez Trucking, had 33 units that drove 3.1 million km in total last year and were involved in seven crashes over the past two years, US Federal Motor Carrier Safety Administration records showed. Company officials were not immediately available for comment.

REUTERS