TORONTO -- Emergency crews say no one was injured when a large section of the Scarborough Bluffs stone face collapsed into Lake Ontario on Sunday afternoon, forcing police to cordon off the area.

Just before 4 p.m. Sunday, beachgoers beneath the cliff side scrambled out of the way as a section of the side of the tall cliff crumbled and fell into the lake.

Images on social media showed some visitors running away from a dust cloud spreading across the beach.

Toronto police said they were called to the area beneath Lookout Point for what felt to witnesses like "an explosion."

A wide pile of rock was seen on the beach beneath the area where the collapse occurred.

Toronto Fire said the collapse of the cliff may have been caused by a boulder that came loose and then fell.

It is not known what caused the collapse of the cliff side.

Lookout Point was cordoned off and police warned anyone visiting the beach below to exercise caution.

Police said they have been warning people of the risks posed by the unstable ground at the top of Lookout Point for a long time and they are glad no one was injured in the collapse.