Authorities evacuated neighbors from a Pittsburgh neighborhood on Wednesday after someone reportedly facing eviction began firing from inside a home, with witnesses saying they heard what sounded like hundreds of shots fired.

The Allegheny County Sheriff's Office said its people were trying to serve the eviction notice when the occupant began firing in the city's Garfield neighborhood. Witnesses reported that hours into the siege, more gunfire erupted after what sounded like hundreds of shots earlier.

A sergeant leading the eviction notice detail suffered an injury unrelated to gunfire and is doing OK, sheriff's office spokesman Mike Manko said.

A state police spokesperson said drones were being used. A large number of police and other first responders were at the scene.

The shooting occurred a few blocks from a children's hospital.

This is a developing story. Check back later for updates.