OKLAHOMA CITY (KFOR) – Firefighters battled a three-alarm fire at an old Oklahoma City Public Schools building early Thursday morning.

Around 2:30 a.m. on Thursday, Oklahoma City firefighters were called to a multi-story building with smoke coming from the structure near N.W. 9th and Klein.

When crews arrived, they realized it was the old Oklahoma City Public Schools Administration Building.

Firefighters had trouble getting into the building, so they were forced to use a saw to open the door.

It took about two hours for crews to put out the fire.

So far, there is no word on a cause.