Authorities in northern Minnesota are pleading with resort owners to keep anglers off a popular and vast lake after a dozen or more people were rescued off an ice floe.

Around midday Tuesday, reports came into the Beltrami County Sheriff’s Office about people fishing on the eastern side of Upper Red Lake who were stranded on a sheet of ice that broke free from the shore amid strong winds.

Rescue personnel from the nearby city of Kelliher rescued 11 people, and there were reports of “many others being rescued by local resorts,” Sheriff Ernie Beitel said in a statement.

As of Wednesday evening, Beitel said, authorities had yet to nail down exactly how many people were saved.

Beitel said the failure of anyone to call 911 or the Sheriff’s Office about the potentially tragic circumstances made the formal and informal rescue operations more dangerous for the responders.

The Sheriff’s Office contacted resorts in the area and urged them to keep anglers from going on the ice, which has iced over early this season to varying thickness because of unseasonably cold weather.

If anglers go on the ice anyway, Beitel said, “doing so risks the lives of our first responders” and others from nearby agencies.

“Like most of Minnesota’s rural areas, our first responders are volunteers,” the sheriff said. “They are our family, our friends and our neighbors. Please don’t put their lives at risk.”

Combined, the surface of Upper and Lower Red Lake covers more than 288,000 acres, making it the largest body of water entirely within Minnesota’s borders.