The 10th annual Sebago Lake ice fishing derby has been canceled after several people and vehicles went through thin ice Saturday, according to the Maine Warden Service.

Seven people, as well as several vehicles, fell through the ice during the first day of the weekend derby, according to spokeswoman Deb Turcotte. No injuries were immediately reported, but Turcotte said she is preparing a formal announcement that the derby is canceled.

Game wardens were prepared for problems, especially after a veteran warden plunged through the ice Friday afternoon while riding an ATV near ice fishing shacks off Raymond Beach.

While the entire 28,771-acre lake has not iced over, organizers hoped the state’s largest ice fishing derby could still be held safely by taking extra precautions. Fishermen were advised not to take their trucks onto the ice and to be wary of pressure ridges where the ice has pushed up.

Maine game warden Sgt. Tim Spahr said the warden service planned to have numerous wardens on patrol and two airboats ready in case someone went through the ice.

This is the third year in 10 that Sebago Lake has had marginal ice for the derby, but the only other year the event was canceled was 2002.