Emergency crews were called to the Red River in Winnipeg to try to rescue two boys who fell through the ice. A passerby rescued one, but his brother remains missing. (CBC)

A six-year-old boy is missing after he and his older brother fell through the ice while playing hockey on the Red River in Winnipeg on Saturday, prompting an emergency rescue effort.

Police and firefighters were still searching for the boy, concentrating on covering an area that extends about three city blocks downstream from the Disraeli Bridge in the city's North Point Douglas area, Const. Natalie Aitken of Winnipeg Police Services said.

She said crews were using inflatable boats on the river, which is ice-covered but has some open patches.

Shortly after the boys fell through the ice, Kole Devisscher, 16, who was driving by, spotted the 10-year-old brother struggling in the water. He grabbed a tow rope out of the back of his truck and headed out on the ice, risking his life.

"I kind of thought about it before I went out there and did what I could to get him out," Devisscher said.

The boy's hands were too cold to grip the rope, so Devisscher made a lasso and hooked him in.

Eyewitnesses estimated the boy was in the water about 15 minutes. They said he was so cold, his legs were barely working and that he kept tripping as he tried to walk.

"He was just screaming and saying he was freezing and his brother was dead. It's pretty sad," Devisscher said.

As he was taken to hospital, emergency crews deployed rescue boats to begin searching for the younger boy.

There was no immediate word on the condition of the rescued boy.

"What started out as a fun event on a relatively nice winter day has really turned into a tragedy," said Aiken.

Disraeli Freeway Bridge, Winnipeg, Manitoba

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