DENVER (AP) — Five children and a man who ran a group home were killed Thursday when their van collided with a tractor-trailer in eastern Colorado, authorities said.

All of the children in the van live at the home for adopted and foster children run by the man, said Kiowa County Sheriff's office spokesman Chris Sorensen. The relationships of the children who died to the man were not immediately known.

A photo provided by the State Patrol showed the front of the van crumpled into the rear of a large livestock trailer. Sorensen said the van collided with the truck on U.S. 287 south of Kit Carson, which is about 130 miles southeast of Denver.

Stacy Stegman, a spokeswoman for the Colorado Department of Transportation, said the accident happened on a stretch of highway under repair. Sorensen said workers have been repairing cracks on the highway for the past month, shutting down one lane and using a flag man to direct traffic.

The collision occurred in the back of a line of traffic about 1,000 feet long, Stegman said. Sorensen said the normal speed limit on the highway is 65 miles per hour, but speeds were reduced because of the construction zone.

The truck was carrying only the driver, who suffered serious injuries, the state patrol said. Sorensen said 13 people were in the van, including six in serious condition and one person who suffered minor injuries.

Sorensen identified the dead as van driver Howard Mitchell; Austyn Ackinson, 11; Tony Mitchell, 4; Tayla Mitchell, 10; Andy Dawson, 13, and Jeremy Franks, 17.

A school district in Eads, about 15 miles south of Kit Carson, also said on its website that the crash involved the Mitchell family. Sorensen said the van was headed to there from Kit Carson.

U.S. 287 is a mostly two-lane highway that cuts across the sparsely populated eastern plains of Colorado. It is popular with truckers on north-south trips through the state.