The highway patrol reported that some of the victims were in a "very, very serious" condition after the crash at the KinderCare building in Orlando.

Police said a silver or greyish Dodge Durango hit another vehicle that then crashed into the building. The Durango left the scene but was found shortly afterwards some distance away.

Police named 26-year-old Robert Corchado as a person of interest they were searching for following the collision and warned he might be attempting to fly out of the state.

The Orlando Sentinel reported a witness as saying the car disappeared inside the day care centre before the driver emerged, apparently unhurt but visibly shaken.

Small children and infants in cots were evacuated outside into the playground after the crash, while several of those injured were taken out on stretchers.

Victims were seen being taken away on stretchers

Parents could be seen waiting to pick up their children and then clutching them in their arms as they were taken to their vehicles by authorities.

Thirteen people have been taken to hospital, while two others were treated at the scene.

Jeezy Jenkins, who was repairing the roof of the petrol station next door, said he saw several small children lying, seriously injured, on the ground inside the building.

"The ones that I did see, I seen blood come out of their mouths, their mouths hit something or whenever because they were bleeding out of their mouths and there was other ones that weren't moving at all, and the teachers were giving them CPR and stuff like that," Click Orlando reported him as saying.

Orange County Mayor Teresa Jacobs called the crash an "absolute tragedy and disaster".

The day care centre's website says the centre provides childcare and learning opportunities for children aged six weeks to 12 years old.