NIAGARA FALLS, N.Y. - An apparent illegal immigrant was rescued from an ice floe about 1.5 kilometres upstream from Niagara Falls, authorities said.

Guards from Ontario Power Generation said they heard the man screaming for help at about 4:30 a.m. Saturday near the company's water intakes near Chippawa, Ont.

Peter Larsen, a control dam operator at the intakes, said if the man hadn't been discovered, "he would have gone through one of those gates and then very likely could have been swept over the falls."

Rescuers in boats plucked the shivering man from the ice floe and got him ashore.

Authorities said the unidentified 42-year-old man had an inflatable air mattress with him and was apparently trying to get to the United States. The ice chunk he was on apparently broke loose.

The man was treated for mild hypothermia before being charged by Canadian immigration authorities.