Fish Wildlife and Parks spokesman Morgan Jacobsen said authorities were still trying to determine if the attacks involved the same bear.
They occurred Monday within a mile of one another in the Gravelly mountains of southwestern Montana.
In the first encounter, two archery hunters from New Mexico were tracking elk when a bear charged and injured both men. It left after being sprayed with bear spray.
That evening, two hunters from Washington were charged by a bear and one of them was mauled. The men fired gunshots at the animal until it left.
Jacobsen says it’s unclear if they hit the bear.