Highway 11 has been closed on both sides of Couchiching First Nation due to standoff.
The OPP said a man barricaded himself inside a residence shortly before 1 p.m. Thursday afternoon, which has prompted the involvement of the provincial police force's emergency response team.
Treaty Three Police are also assisting.
A perimeter has been set up surrounding the residence and police are asking the public to stay away.
Highway 11, approximately seven kilometres east of Fort Frances between the CN rail crossing and the Noden Causeway is located within the perimeter.
