BRASILIA, Brazil (AP) — A towering slab of rock broke off a cliff Saturday and toppled onto pleasure boaters drifting near a waterfall on a Brazilian lake.

Local officials said at least six people were killed and 32 injured. As many are 20 others were reported missing.

Video images show a gathering of small boats moving slowly near the sheer rock cliff on Furnas Lake. Then, a fissure appears in the cliff and a huge piece topples onto at least two of the vessels.

The press office of Minas Gerais state told the Associated Press that the fire department deployed divers and helicopters to help.