In the days leading up to President Donald Trump’s inauguration, three nights of protests and riots broke out at Standing Rock as demonstrators continue to oppose the Dakota Access Pipeline.

Thousands of Native Americans, environmental activists and protesters have since August stood in protest of the $3.8 billion (£3 billion) project that had intended to cross underneath North Dakota’s Lake Oahe, a water source upstream from the Standing Rock Sioux reservation. Protesters fear the pipeline could damage drinking water and desecrate sacred grounds.

In December a US Department of Defence agency denied permission for the pipeline to pass under the lake. Members of the Standing Rock Sioux have since asked protesters to “head home with our most heartfelt thanks”. Many have, but some have remained, with further clashes seen between protesters and police over the past week.

A total of 27 people were arrested over the course of Monday, Tuesday and Wednesday last week when protesters accessed Backwater Bridge, according to Morton County Sheriff’s Department.

Reports claim police used tear gas, pepper spray and rubber bullets on the protesters. A statement from members of the Sacred Stone Camp in Standing Rock claimed protesters were unarmed when, on Martin Luther King day, they led a prayer walk to the razor wire barricade 700 feet away from the drill pad where the pipeline had been set to cross the Missouri river.

Police posted a video of the protesters using wire cutters to cut through the barbed wire and claimed these were then turned into circular, Frisbee shapes and thrown at officers. A total of 16 people were arrested on Monday and Tuesday for a number of offences, including engaging in a riot and assault on a peace officer.

On Wednesday protesters allegedly “became more aggressive by throwing projectiles” at officers, who then deployed less-than-lethal munitions of direct impact sponge rounds, drag stabilizer bean bag rounds, hand deployed pepper spray canisters and smoke riot control CS canisters.

Sioux from Standing Rock claim victory over Dakota Pipeline Show all 21 1 /21 Sioux from Standing Rock claim victory over Dakota Pipeline Sioux from Standing Rock claim victory over Dakota Pipeline CANNON BALL, ND - DECEMBER 05: Despite blizzard conditions, military veterans march in support of the "water protectors" at Oceti Sakowin Camp on the edge of the Standing Rock Sioux Reservation on December 5, 2016 outside Cannon Ball, North Dakota. Over the weekend a large group of military veterans joined native Americans and activists from around the country who have been at the camp for several months trying to halt the construction of the Dakota Access Pipeline. Yesterday the US Army Corps of Engineers announced that it will not grant an easement for the pipeline to cross under a lake on the Sioux Tribes Standing Rock reservation. The proposed 1,172-mile-long pipeline would transport oil from the North Dakota Bakken region through South Dakota, Iowa and into Illinois. (Photo by Scott Olson/Getty Images) Getty Images Sioux from Standing Rock claim victory over Dakota Pipeline CANNON BALL, ND - DECEMBER 04: Fireworks fill the night sky above Oceti Sakowin Camp as activists celebrate after learning an easement had been denied for the Dakota Access Pipeline near the edge of the Standing Rock Sioux Reservation on December 4, 2016 outside Cannon Ball, North Dakota. The US Army Corps of Engineers announced today that it will not grant an easement to the Dakota Access Pipeline to cross under a lake on the Sioux Tribes Standing Rock reservation, ending a months-long standoff. (Photo by Scott Olson/Getty Images) Getty Images Sioux from Standing Rock claim victory over Dakota Pipeline CANNON BALL, ND - DECEMBER 05: Despite blizzard conditions, military veterans march in support of the "water protectors" at Oceti Sakowin Camp on the edge of the Standing Rock Sioux Reservation on December 5, 2016 outside Cannon Ball, North Dakota. Over the weekend a large group of military veterans joined native Americans and activists from around the country who have been at the camp for several months trying to halt the construction of the Dakota Access Pipeline. Yesterday the US Army Corps of Engineers announced that it will not grant an easement for the pipeline to cross under a lake on the Sioux Tribes Standing Rock reservation. The proposed 1,172-mile-long pipeline would transport oil from the North Dakota Bakken region through South Dakota, Iowa and into Illinois. (Photo by Scott Olson/Getty Images) Getty Images Sioux from Standing Rock claim victory over Dakota Pipeline CANNON BALL, ND - DECEMBER 04: Fireworks fill the night sky above Oceti Sakowin Camp as activists celebrate after learning an easement had been denied for the Dakota Access Pipeline near the edge of the Standing Rock Sioux Reservation on December 4, 2016 outside Cannon Ball, North Dakota. The US Army Corps of Engineers announced today that it will not grant an easement to the Dakota Access Pipeline to cross under a lake on the Sioux Tribes Standing Rock reservation, ending a months-long standoff. (Photo by Scott Olson/Getty Images) Getty Images Sioux from Standing Rock claim victory over Dakota Pipeline CANNON BALL, ND - DECEMBER 05: Despite blizzard conditions, military veterans march in support of the "water protectors" at Oceti Sakowin Camp on the edge of the Standing Rock Sioux Reservation on December 5, 2016 outside Cannon Ball, North Dakota. Over the weekend a large group of military veterans joined native Americans and activists from around the country who have been at the camp for several months trying to halt the construction of the Dakota Access Pipeline. Yesterday the US Army Corps of Engineers announced that it will not grant an easement for the pipeline to cross under a lake on the Sioux Tribes Standing Rock reservation. The proposed 1,172-mile-long pipeline would transport oil from the North Dakota Bakken region through South Dakota, Iowa and into Illinois. (Photo by Scott Olson/Getty Images) Getty Images Sioux from Standing Rock claim victory over Dakota Pipeline CANNON BALL, ND - DECEMBER 04: Native American and other activists celebrate after learning an easement had been denied for the Dakota Access Pipeline at Oceti Sakowin Camp on the edge of the Standing Rock Sioux Reservation on December 4, 2016 outside Cannon Ball, North Dakota. The US Army Corps of Engineers announced today that it will not grant an easement to the Dakota Access Pipeline to cross under a lake on the Sioux Tribes Standing Rock reservation, ending a months-long standoff. (Photo by Scott Olson/Getty Images) Getty Sioux from Standing Rock claim victory over Dakota Pipeline CANNON BALL, ND - DECEMBER 04: Chief Arvol Looking Horse of the Lakota/Dakota/Nakota Nation listens to speakers during an interfaith ceremony at Oceti Sakowin Camp on the edge of the Standing Rock Sioux Reservation on December 4, 2016 outside Cannon Ball, North Dakota. Native Americans and activists from around the country have been gathering at the camp for several months trying to halt the construction of the Dakota Access Pipeline. Today the US Army Corps of Engineers announced that it will not grant an easement for the pipeline to cross under a lake on the Sioux Tribes Standing Rock reservation, ending the months-long standoff. The proposed 1,172-mile-long pipeline would transport oil from the North Dakota Bakken region through South Dakota, Iowa and into Illinois. (Photo by Scott Olson/Getty Images) Getty Images Sioux from Standing Rock claim victory over Dakota Pipeline CANNON BALL, ND - DECEMBER 04: An Native American activist rides down fom a ridge which overlooks Oceti Sakowin Camp on the edge of the Standing Rock Sioux Reservation on December 4, 2016 outside Cannon Ball, North Dakota. Native Americans and activists from around the country have been gathering at the camp for several months trying to halt the construction of the Dakota Access Pipeline. The proposed 1,172-mile-long pipeline would transport oil from the North Dakota Bakken region through South Dakota, Iowa and into Illinois. (Photo by Scott Olson/Getty Images) Getty Images Sioux from Standing Rock claim victory over Dakota Pipeline CANNON BALL, ND - DECEMBER 05: Despite blizzard conditions, military veterans march in support of the "water protectors" at Oceti Sakowin Camp on the edge of the Standing Rock Sioux Reservation on December 5, 2016 outside Cannon Ball, North Dakota. Over the weekend a large group of military veterans joined native Americans and activists from around the country who have been at the camp for several months trying to halt the construction of the Dakota Access Pipeline. Yesterday the US Army Corps of Engineers announced that it will not grant an easement for the pipeline to cross under a lake on the Sioux Tribes Standing Rock reservation. The proposed 1,172-mile-long pipeline would transport oil from the North Dakota Bakken region through South Dakota, Iowa and into Illinois. (Photo by Scott Olson/Getty Images) Getty Images Sioux from Standing Rock claim victory over Dakota Pipeline CANNON BALL, ND - DECEMBER 04: Political activist Cornel West listen to speakers during an interfaith ceremony at Oceti Sakowin Camp on the edge of the Standing Rock Sioux Reservation on December 4, 2016 outside Cannon Ball, North Dakota. Native Americans and activists from around the country have been gathering at the camp for several months trying to halt the construction of the Dakota Access Pipeline. Today the US Army Corps of Engineers announced that it will not grant an easement for the pipeline to cross under a lake on the Sioux Tribes Standing Rock reservation, ending the months-long standoff. The proposed 1,172-mile-long pipeline would transport oil from the North Dakota Bakken region through South Dakota, Iowa and into Illinois. (Photo by Scott Olson/Getty Images) Getty Images Sioux from Standing Rock claim victory over Dakota Pipeline Activists hold hands during a prayer circle as they try to surround the entire camp at Oceti Sakowin Camp on the edge of the Standing Rock Sioux Reservation on December 4, 2016 outside Cannon Ball, North Dakota. Native Americans and activists from around the country gather at the camp trying to halt the construction of the Dakota Access Pipeline. / AFP / JIM WATSON (Photo credit should read JIM WATSON/AFP/Getty Images) AFP/Getty Images Sioux from Standing Rock claim victory over Dakota Pipeline Activists celebrate at Oceti Sakowin Camp on the edge of the Standing Rock Sioux Reservation on December 4, 2016 outside Cannon Ball, North Dakota, after hearing that the Army Corps of Engineers has denied the current route for the Dakota Access pipeline. / AFP / JIM WATSON (Photo credit should read JIM WATSON/AFP/Getty Images) AFP/Getty Images Sioux from Standing Rock claim victory over Dakota Pipeline CANNON BALL, ND - DECEMBER 04: Chief Arvol Looking Horse (L) of the Lakota/Dakota/Nakota Nation listens as political activist Cornel West speaks during an interfaith ceremony at Oceti Sakowin Camp on the edge of the Standing Rock Sioux Reservation on December 4, 2016 outside Cannon Ball, North Dakota. Native Americans and activists from around the country have been gathering at the camp for several months trying to halt the construction of the Dakota Access Pipeline. Today the US Army Corps of Engineers announced that it will not grant an easement for the pipeline to cross under a lake on the Sioux Tribes Standing Rock reservation, ending the months-long standoff. The proposed 1,172-mile-long pipeline would transport oil from the North Dakota Bakken region through South Dakota, Iowa and into Illinois. (Photo by Scott Olson/Getty Images) Getty Images Sioux from Standing Rock claim victory over Dakota Pipeline CANNON BALL, ND - DECEMBER 05: Military veterans from Southern California collect firewood for their campsite at Oceti Sakowin Camp on the edge of the Standing Rock Sioux Reservation on December 5, 2016 outside Cannon Ball, North Dakota. Over the weekend a large group of military veterans joined native Americans and activists from around the country who have been at the camp for several months trying to halt the construction of the Dakota Access Pipeline. Yesterday the US Army Corps of Engineers announced that it will not grant an easement for the pipeline to cross under a lake on the Sioux Tribes Standing Rock reservation. The proposed 1,172-mile-long pipeline would transport oil from the North Dakota Bakken region through South Dakota, Iowa and into Illinois. (Photo by Scott Olson/Getty Images) Getty Images Sioux from Standing Rock claim victory over Dakota Pipeline CANNON BALL, ND - DECEMBER 05: Despite blizzard conditions, military veterans march in support of the "water protectors" at Oceti Sakowin Camp on the edge of the Standing Rock Sioux Reservation on December 5, 2016 outside Cannon Ball, North Dakota. Over the weekend a large group of military veterans joined native Americans and activists from around the country who have been at the camp for several months trying to halt the construction of the Dakota Access Pipeline. Yesterday the US Army Corps of Engineers announced that it will not grant an easement for the pipeline to cross under a lake on the Sioux Tribes Standing Rock reservation. The proposed 1,172-mile-long pipeline would transport oil from the North Dakota Bakken region through South Dakota, Iowa and into Illinois. (Photo by Scott Olson/Getty Images) Getty Images Sioux from Standing Rock claim victory over Dakota Pipeline CANNON BALL, ND - DECEMBER 03: Activists participate in an art project conceived by Cannupa Hunska Luger, from the Standing Rock Sioux Tribe, at Oceti Sakowin Camp on the edge of the Standing Rock Sioux Reservation on December 3, 2016 outside Cannon Ball, North Dakota. Native Americans and activists from around the country have been gathering at the camp for several months trying to halt the construction of the Dakota Access Pipeline. The proposed 1,172-mile-long pipeline would transport oil from the North Dakota Bakken region through South Dakota, Iowa and into Illinois. (Photo by Scott Olson/Getty Images) Getty Images Sioux from Standing Rock claim victory over Dakota Pipeline CANNON BALL, ND - DECEMBER 05: Military veterans are briefed on cold-weather safety issues and their overall role at Oceti Sakowin Camp on the edge of the Standing Rock Sioux Reservation on December 5, 2016 outside Cannon Ball, North Dakota. Over the weekend a large group of military veterans joined native Americans and activists from around the country who have been at the camp for several months trying to halt the construction of the Dakota Access Pipeline. Yesterday the US Army Corps of Engineers announced that it will not grant an easement for the pipeline to cross under a lake on the Sioux Tribes Standing Rock reservation. The proposed 1,172-mile-long pipeline would transport oil from the North Dakota Bakken region through South Dakota, Iowa and into Illinois. (Photo by Scott Olson/Getty Images) Getty Images Sioux from Standing Rock claim victory over Dakota Pipeline CANNON BALL, ND - DECEMBER 04: Native American and other activists celebrate after learning an easement had been denied for the Dakota Access Pipeline at Oceti Sakowin Camp on the edge of the Standing Rock Sioux Reservation on December 4, 2016 outside Cannon Ball, North Dakota. The US Army Corps of Engineers announced today that it will not grant an easement to the Dakota Access Pipeline to cross under a lake on the Sioux Tribes Standing Rock reservation, ending a months-long standoff. (Photo by Scott Olson/Getty Images) Getty Images Sioux from Standing Rock claim victory over Dakota Pipeline CANNON BALL, ND - DECEMBER 04: Native American activists celebrate after learning an easement had been denied for the Dakota Access Pipeline at Oceti Sakowin Camp on the edge of the Standing Rock Sioux Reservation on December 4, 2016 outside Cannon Ball, North Dakota. The US Army Corps of Engineers announced today that it will not grant an easement to the Dakota Access Pipeline to cross under a lake on the Sioux Tribes Standing Rock reservation, ending a months-long standoff. (Photo by Scott Olson/Getty Images) Getty Images Sioux from Standing Rock claim victory over Dakota Pipeline CANNON BALL, ND - DECEMBER 04: Native American and other activists celebrate after learning an easement had been denied for the Dakota Access Pipeline at Oceti Sakowin Camp on the edge of the Standing Rock Sioux Reservation on December 4, 2016 outside Cannon Ball, North Dakota. The US Army Corps of Engineers announced today that it will not grant an easement to the Dakota Access Pipeline to cross under a lake on the Sioux Tribes Standing Rock reservation, ending a months-long standoff. (Photo by Scott Olson/Getty Images) Getty Images Sioux from Standing Rock claim victory over Dakota Pipeline Activists celebrate at Oceti Sakowin Camp on the edge of the Standing Rock Sioux Reservation on December 4, 2016 outside Cannon Ball, North Dakota, after hearing that the Army Corps of Engineers has denied the current route for the Dakota Access pipeline. The US Army Corps of Engineers on Sunday announced they will no longer allow the Dakota Access Pipeline to cross under a lake on the Standing Rock reservation in North Dakota, marking a huge win for Native Americans and protesters who had long opposed the construction. / AFP / JIM WATSON (Photo credit should read JIM WATSON/AFP/Getty Images) AFP/Getty Images

One protester, who had been injured in the face, was taken to the Sanford Medical Centre in Bismark by ambulance.

The North Dakota National Guard had deployed a missile defense system to the area near the protest site, but it was unarmed and being used only for observation purposes, said Amber Balken, a spokeswoman for the North Dakota National Guard.

The number of people arrested since 10 August is now 624, police said.

On Wednesday, the US army began gathering information to prepare an environmental impact statement on the easement to cross Lake Oahe.

President Trump has not commented specifically on the pipeline, which had been intended to carry oil from western North Dakota to a shipping point in Illinois, but his press secretary Sean Spicer hinted that the President may move forward with the project.

“I’m not going to get in front of the President’s executive actions, but I will tell you that areas like the Dakota and Keystone pipeline, areas that we can increase jobs, increase economic growth, and tap into America’s energy supply more, that’s something that he has been very clear about,” he said this week.