NIAGARA FALLS, Ont. - A Canadian police officer conducted a daring rescue on the Niagara River while suspended by a rope from a helicopter early Saturday.

The officer helped two New York State officers who became stranded while conducting their own rescue.

Const. Shawn Black of the Niagara Parks Police lowered himself on a rope from a helicopter to a stranded boat with the two American officers on board and helped bring them to land, said Const. John Gayder, who coordinates the Canadian police force's High Angle River Team.

"He (Black) attached himself to one of the stranded officers, they were lifted into the air and flown back to Goat Island and then the process was repeated for the second officer," Gayder said in a phone interview.

The rescue took place about 900 metres from the falls, around a point when the current picks up greater speed, Gayder said.

"It would not take long for a person in the water there to be swept over the Horseshoe Falls."

The helicopter used was owned by Niagara Helicopters, a private company that does tours over the falls. The company's choppers are used when police helicopters are not available.

Ruedi Hafen, the pilot of the chopper, said although the rescue went off like "clock work" there were some difficult moments.

"It's very tricky, with the wind and the fast moving water and the boat wasn't stable in the water," the 58-year-old veteran with 30 years of flying experience said in an interview.

The two American officers were breathing much easier once they were on dry land, said Hafen.

"Those guys, they were really relieved, they were so happy," he said with a chuckle.

The Americans were with the Niagara State Park Police and were on the river going to a civilian craft that was in a part of the river that is prohibited to boats.

The Buffalo News reported that the American police received a call at about 2 a.m. Saturday that the civilian craft with four people on board became disabled.

It wasn't clear whether the boat ran out gas or had engine trouble, the American newspaper said. The U.S. officers were able to get the civilians to shore but lost their bearings in the fog and darkness and had to drop anchor.

But the swift currents of the river made it very perilous for the officers relying on a boat tethered to an anchor by a length of rope, Gayder said.

"Their lives were literally hanging on that rope, it was important to get them off," he said. "The boat wasn't going to be able to come out of the rapids under its own power, it's (the current) just too strong there."

Their Canadian counterparts received the call to come to their assistance at about 6 a.m. and the rescue was completed by 8 a.m., Gayder said. The Canadian force was called to help because there was no helicopter available on the American side to allow the U.S. force to do the rescue.

This type of rescue is done extremely rarely, Gayder said, with this incident being only the second occasion.

"We train for all these contingencies, this is something we do quite regularly, we've done over 100 practice flights like this," said Gayder, who is also trained to do such work.

"It's quite exciting, not a lot of people get to that, it's very exciting."

Hafen, who has done a considerable amount of rescue work in his 30 years of flying in the area, said he had never done one like this.

"Before this morning I thought I'd seen it all," he said.

"It was very neat because here is a Canadian team rescuing American officers."