A witness and firefighter give their accounts of the jump and rescue operation AP

A man who apparently tried to kill himself by jumping off the top of Niagara falls yesterday became only the second person in history to survive the 54 metre (180ft) plunge unattached and with no protective device.

The man, believed to be in his late 30s, survived after leaping into the rapids above the Horseshoe falls, one of Niagara's three waterfalls.

He then desperately resisted rescue attempts, swimming away from rescuers who tried to pull him from the near-freezing waters and climbing out of a sling dropped by a helicopter, police said.

A witness alerted police after seeing the man jump into the Canadian side of the falls. He emerged near the base of the falls a short time later, but as specially trained rescue crews tried to save his life, he swam away from them towards the middle of the river, according to Doug Kane, the Niagara Parks police chief.

A private helicopter was called and the pilot used wind from the blades to generate a current which pushed him closer to shore where rescuers could reach him.

"He wasn't co-operative," the pilot, Ruedi Hafen, told the Associated Press. "He didn't try to be helpful. We had a sling on him and he got out of it."

After about 30 minutes in the icy waters, much of that spent resisting rescue attempts, the man was hauled to dry land by a firefighter and a rescue worker. He was taken to Niagara Falls hospital suffering from hypothermia and a head injury.

"He was on a suicide mission, I assume," Hafen said. "I've never, in my career, seen someone so tough, swimming between the ice."

The last person known to survive a plunge over the falls was Kirk Jones, a former auto parts salesman from Michigan who climbed down a small embankment and jumped into the Niagara river on 20 October 2003.

Jones said he had been depressed and drinking when he went over the famous falls.

At least 17 people, not including those trying to kill themselves, are known to have gone over the falls.

Niagara falls consists of three waterfalls: the American falls, Horseshoe falls and Bridal Veil falls. The Horseshoe falls on the border of Canada and the US sends 110,000-168,000 cubic metres of water over its edge every minute and is one of the world's most popular tourist attractions.