Investigators Head to Ferris Wheel Accident at Tennessee Fair

Investigators are headed to the scene of a Greeneville, Tennessee, fair after a ferris wheel cabin flipped Monday night, spilling three children about 35 to 45 feet to the ground.

The incident happened around 6:15 p.m. at the Greene County Fair.

It's still unclear what caused the cabin to tip over, the Greenville Police said this morning.

The youngest of the three victims is in serious condition with a head injury, police said this morning. Two victims were alert and speaking last night, police said. Their names were not released.

"We would like to extend our thoughts and prayers for those injured tonight at the fair. We are deeply shocked and saddened," the Greene County Fair said in a statement. "All rides have been shut down until further notice."

As investigators head to Greeneville, authorities said today that the inspections could take a few days.

Fair grounds officials said today they do not know when the ride was last inspected.

The fair, which began Aug. 7, runs through Aug. 13.

ABC News' Steve Osunsami and Brandon Baur contributed to this report.