CHATTANOOGA, Tenn. » Police in southeastern Tennessee say six people have been killed in a nine-vehicle wreck on Interstate 75.

Chattanooga Police Department spokesman Kyle Miller says the accident happened around 7:10 p.m. Thursday on I-75 northbound near the suburb of Ooltewah.

He says investigators will be working overnight to determine the cause of the crash.

Police believe more than 15 people were involved; the exact number is still being determined because multiple groups were taken to local hospitals.

The identities of the victims were not immediately released.

Northbound lanes of I-75 were shut down after the accident and traffic was redirected. Police say the lanes will likely be closed into the early morning hours.