Protesters, security clash near North Dakota oil pipeline

Protestors gather at the blocked entrance to a construction site for the Dakota Access Pipeline to express their opposition to the pipeline, near an encampment where hundreds of people have gathered to join the Standing Rock Sioux Tribe's to protest against the construction of the new oil pipeline, near Cannon Ball, North Dakota, on September 3, 2016.
The Indian reservation in North Dakota is the site of the largest gathering of Native Americans in more than 100 years. Indigenous people from across the US are living in camps on the Standing Rock reservation as they protest the construction of the new oil pipeline which they fear will destroy their water supply.
 / AFP / Robyn BECK        (Photo credit should read ROBYN BECK/AFP/Getty Images)

Protestors gather at the blocked entrance to a construction site for the Dakota Access Pipeline to express their opposition to the pipeline, near an encampment where hundreds of people have gathered to join the Standing Rock Sioux Tribe's to protest against the construction of the new oil pipeline, near Cannon Ball, North Dakota, on September 3, 2016. The Indian reservation in North Dakota is the site of the largest gathering of Native Americans in more than 100 years. Indigenous people from across the US are living in camps on the Standing Rock reservation as they protest the construction of the new oil pipeline which they fear will destroy their water supply. / AFP / Robyn BECK (Photo credit should read ROBYN BECK/AFP/Getty Images)

BISMARCK, N.D. (AP) — A protest of a four-state oil pipeline turned violent after tribal officials say construction crews destroyed American Indian burial and cultural sites on private land in southern North Dakota.

Morton County Sheriff’s Office spokeswoman Donnell Preskey says four security guards and two guard dogs were injured after several hundred protesters confronted construction crews Saturday afternoon at the site just outside the Standing Rock Sioux reservation.

Tribe spokesman Steve Sitting Bear says protesters reported that six people had been bitten by security dogs, and at least 30 people were pepper-sprayed.

Preskey says there were no law enforcement personnel at the site when the incident occurred.

She says the crowd dispersed when officers arrived and no one was arrested.