A lightning strike on a Lake Superior beach in Minnesota injured five people, including a 9-year-old Wisconsin boy who later died, authorities said on Sunday.

Sergeant Wade Rasch of the St. Louis County Sheriff's Office said that a family party was on a friend's sailboat that took shelter from a sudden thunderstorm at Minnesota Point, near the Superior entry to the Duluth-Superior harbor, on Saturday.

Lightning struck as the group was in shallow water near the beach, he said.

Luke Voigt, 9, of Iron River, Wisconsin, was flown by helicopter to a Duluth hospital, where he died. Four other injured people were taken to Duluth hospitals, and two have been released, Rasch said.

(Reporting by Ian Simpson; Editing by Cynthia Osterman)