Four people are dead including two children after a head-on collision in northern Alberta. Police say they believe alcohol was a factor.

Lac La Biche RCMP say the collision happened Sunday night at around 7 p.m. on Highway 858 near Lac La Biche, which is located about 200 kilometres northeast of Edmonton.

Police say that a truck carrying three people collided with an SUV containing a family of five from Edmonton.

A 34-year-old woman and two children, boys aged nine and four, in the SUV were pronounced dead on the scene. The 33-year-old male driver of the SUV and another child in that vehicle suffered life-threatening injuries and were airlifted to Edmonton.

A 23-year-old female passenger in the truck was pronounced dead on the scene. She was from Plamondon. The driver, a 21-year-old man from Edmonton, and a 20-year-old male passenger from Plamondon, were also airlifted to Edmonton with life-threatening injuries.

Alcohol is believed to have been a factor in the crash, according to RCMP.

Police say their “thoughts and prayers are with all the families of the deceased during this difficult time.” They say the names of the victims will not be released.