A van carrying Amish on an interstate highway veered out of control, overturned and ejected some passengers Sunday, killing five people and injuring 11, authorities said.

Two adults and three children were killed when the southbound van veered onto the grassy median, flipped over and came to rest in the northbound lanes of the highway about 50 miles northeast of Indianapolis, State Police Sgt. Rod Russell said.

No other vehicles were involved in the crash, he said.

The condition of the injured was unclear Sunday evening.

Some of the victims hailed from an Amish community in the Fort Wayne area, about 50 miles to the northeast. Authorities were trying to verify whether some victims came from other Amish communities across Indiana.

"We do believe that some were Amish," Russell said.

Amish people generally shun modern conveniences but sometimes enlist non-Amish as drivers.

At the scene, the van lay on its side with its roof gone. Traffic in both directions was stopped as authorities used the highway to land medical helicopters.

Seven such helicopters were called to the scene, said Bill Gosnell, director of the Delaware County Emergency Management Agency.

It was not clear at first how many people had been riding in the van, as survivors gave conflicting stories of 15, 16 or even 17 passengers. That led police and other responders to search for additional injured people until it became clear all people in the van were accounted for.

"It's controlled chaos, is what it is, when you have a situation like this," with ejections and many people injured, Russell said.

Southbound lanes of I-69 reopened about two hours after the crash. Northbound lanes remained closed nearly four hours afterward.

The crash occurred about 20 miles from the site of an April 2006 collision between a Taylor University van and a semitrailer rig that killed four students and a university employee.

The crash resulted in a highly publicized case of mistaken identity after the family of a student believed dead turned out to be another girl originally thought to have survived the crash.

In April, four Amish riding in a pickup were among eight people killed in a crash on the Indiana Toll Road.