A 3-year-old boy was killed and his grandmother suffered "significant injuries" in a dog attack in Otter Tail County on Sunday, the sheriff's office said.

The boy climbed into "an outside enclosed area" where an American bulldog was being kept, the sheriff's office said. The dog attacked him, and his 51-year-old grandmother stopped the attack, then drove the boy to a nearby emergency room.

The toddler died of his injuries at the ER, and the grandmother was taken to a hospital in Fargo, North Dakota.

The attack happened at the grandmother's house, just west of New York Mills, Minnesota.

The dog was killed, the sheriff's office said, "and there are no ongoing safety concerns."

New York Mills is about midway between Fargo and Brainerd, Minnesota.