Rescuers pulled two men from choppy waters in Lake Michigan and searched for a third boater Wednesday after the trio's 16-foot boat capsized and sank a mile off shore, police said.

The incident northeast of the city's Navy Pier was reported shortly before 9 a.m. while a small craft advisory was in effect.

"We are still actively searching for another individual," said Chicago Police Lt. Christopher Kennedy, who commands the department's marine and helicopter unit.

Kennedy said the two men — in their 30s or 40s — were in serious condition with mild hypothermia and were being treated at a nearby hospital. They had been in the water up to 35 feet deep for as long as two hours, he said.

"It's rough, it's choppy," he said.

A small craft advisory was issued for the lake around 7 a.m. Wednesday and by midmorning, winds were gusting around 20 knots, said National Weather Service Meteorologist Nathan Marsili.

The lake's water temperature was about 65 degrees.