Authorities in North Dakota are investigating a report of multiple shots fired during a weekend protest against the construction of the Dakota Access oil pipeline.
Morton County sheriff's spokesman Rob Keller on Sunday said the report of shots fired was received Saturday morning, when about 500 people were demonstrating outside a work yard for the pipeline in Mandan, a community adjacent to the state capital of Bismarck and about 50 miles north from an area where hundreds of protesters have been camping in for months. No one was injured in the incident.
Keller says authorities are trying to determine who fired the weapon.
Nobody was arrested during Saturday's protest.
The four-state, 1,200-mile pipeline is complete except for under the Missouri River in North Dakota.