A teenager died and another remains missing after four youths fell through the ice on the Rideau River in the southern end of Ottawa before midnight on Wednesday.

Police said emergency crews responded to a call about four teenagers falling into the river from Nichols Island Road at 11:44 p.m.

They added that two of the teenagers were immediately rescued from the water and transported to the hospital by paramedics, while a 16-year-old youth and a 17-year-old boy are still missing and believed to be in the water.

Police said the rescue operation took place in "very difficult conditions," involving surface and water search.

Police divers later retrieved the body of one of the missing teenagers.

The search for the second missing teenager was halted overnight and is expected to resume in the morning.

Three police vehicles were parked near the Long Island locks on the Rideau Canal on a rainy Thursday morning.

Yellow warning tape was wrapped around the locks near the river, where a thin layer of ice appeared to extend outward from the shore.