MOORHEAD — Moorhead police say a young brother and sister were found playing on a highway after leaving their locked home as their parents slept.

Police say the 3-year-old boy and his 2-year-old sister were seen playing on U.S. Highway 75 Wednesday morning. A passer-by called police after spotting the children.

Police say the boy got on a high chair to unlock the door and go outside. The children were not hurt.

Police brought the children to the police station, and neighbors helped police find the parents, who had been sleeping at home.

Police Lt. Tory Jacobson said the boy showed strong curiosity and was manipulating doors at the police station.

The children are back with their parents, and the Department of Social Services is working with the family.