The suspected shooter — believed to be a boyfriend of one of the victims — is also dead, police said.
Police believe the suspect drove to the home where a birthday party was being held and opened fire before killing himself. No children were injured in the shooting.
Police are investigating a possible motive.
“Words fall short to describe the tragedy that took place this morning,” Colorado Springs Police Chief Vince Niski said. “As the chief of police, as a husband, as a father, as a grandfather, as a member of this community, my heart breaks for the families who have lost someone they love and for the children who have lost their parents.
“From the officers who responded to the shooting to the investigators still on scene, we are all left incredibly shaken.”
Police have yet to name the victims, saying they are working to notify their families.