Toronto Fire is investigating after a sinkhole opened up underneath a parked school bus in the Beaches.

Firefighters were called to Balsam Avenue, north of Queen Street, shortly after 4:30 p.m.

Images from the scene showed a large break in the road underneath the bus. Toronto Fire said it measured around 10 feet wide and four feet deep.

There were no children on board when the sinkhole formed and no injuries were reported.

It is not yet clear what caused the hole to form.

Firefighters are checking for a possible water main break or gas leak in the area.