MANKATO, MN (AP) -

A fire has caused heavy damage at a YMCA indoor skate park in the southern Minnesota city of Mankato.

The fire at the Chesley Roller Sport Park was reported shortly after 9:30 a.m. Saturday. The Free Press reports the structure was fully engulfed by the time firefighters arrived at the park, which is just down the block from a fire station.

Nobody was inside the skate park at the time. It's owned by the Mankato Family YMCA, which had been remodeling the park and had mostly completed the work.

Mankato Family YMCA CEO John Kind was on the scene. He says his heart sank when he saw the fire, and he says he'll convene an executive board meeting.