Authorities in Colorado are investigating after five people, including three children, were killed when an Amtrak train collided with a van Sunday morning.

The Colorado State Patrol said in a statement that a 2005 Chrysler Town & Country failed to yield right of way to the train and was struck at 9:45 a.m. near Trinidad. The van’s driver and three of the six passengers died at the scene. A fifth passenger was taken to the hospital and was later declared dead.

According to The Denver Channel, a Colorado State Trooper said a girl in the van was flown to Children’s Hospital in Aurora with serious injuries. She was the only member of the family in the van to survive.

Authorities will release the names of the van's occupants once relatives are notified.

An Amtrak spokeswoman tells the station that more than 280 passengers were on board at the time of the crash. No one on the train was injured.

The Denver Post reported that the spokeswoman says the Southwest Chief train, which travels between Chicago and Los Angeles, resumed its route at 5 p.m.

Authorities are investigating but neither alcohol nor drug use is suspected.

The Associated Press contributed to this report.