Two children were severely burned in northern Minnesota after they inadvertently set fire to a shed where they were playing, authorities said.

The fire broke out shortly after 8 p.m. Saturday on the northern edge of the Fond du Lac Reservation along Hwy. 2 in Culver Township, roughly 25 miles northwest of Duluth, according to the St. Louis County Sheriff's Office.

Sheriff's deputies called to the scene found the children, ages 5 and 6, with "severe burns to their bodies," a Sheriff's Office statement said.

The children had tipped over a gasoline can in the shed, and some of it spilled on the floor, the Sheriff's Office said.

"The children then attempted to clean up the spilled gasoline using an electric Shop-Vac that ignited in flames," the Sheriff's Office statement continued, "causing the children's clothing to catch fire, as well as the shed."

Deputies learned that both children suffered second-degree burns to approximately 20 percent of their bodies. They are being treated at a nearby hospital. The children's or parents' names have not been released.