CANNON BALL, N.D. - About 50 people began a four-day prayer walk Thursday, Feb. 22, from the Standing Rock Sioux Reservation, one year after the main Dakota Access Pipeline opposition camp was forced to close.

Participants said they wanted to honor the Oceti Sakowin camp, which brought thousands of people together as Native American tribes fought to protect their water and sacred sites.

"Our hearts are beginning to heal by making the journey back here," said Raymond Kingfisher of the Northern Cheyenne Tribe.

The walk started with prayers at a teepee set up south of the Cannonball Bridge. The event began at 2 p.m., coinciding with the deadline the U.S. Army Corps of Engineers and Gov. Doug Burgum set on Feb. 22, 2017, for the Oceti Sakowin camp to close.

Nathan Phillips, a member of the Omaha tribe, led participants in prayer songs as they walked north on Highway 1806, retracing the same steps across the Cannonball River that residents of the camp took a year earlier. Most left the camp voluntarily ahead of Burgum's deadline, with law enforcement in riot gear and military vehicles removing the final residents on Feb. 23, 2017.

Phillips, who stayed at the camp from November 2016 through its closure, said he was inspired by a dream to organize the prayer walk.

"This is something that I have to do," he said.

Phillips raised an eagle staff as the group stopped to hold a moment of silence at the entrance to the Oceti Sakowin camp, which is on land managed by the Corps of Engineers. The field that was once covered with teepees, tents, wooden structures and flags representing tribes from around the world is now marked with no trespassing signs that state it is property of the U.S. government.

Participants concluded Thursday's walk with a prayer at the Backwater Bridge, the site of violent clashes between protesters and law enforcement.

The group, which included people from Standing Rock and others who traveled from out of state, plans to continue walking on segments of Highway 1806 over the next few days, concluding on Sunday in Mandan.

Alycia Yellow Eyes, a Standing Rock Sioux Tribe member who lives in Cannon Ball, said she wanted to participate "to let the rest of the world know that nobody forgot, and to regain some healing, get some strength back in what it is we're doing."

Yellow Eyes said her interest in helping the Oceti Sakowin camp was to protect the Missouri River that she grew up along.

Even though oil is now flowing beneath Lake Oahe, a dammed segment of the Missouri River less than a mile north of the reservation, Yellow Eyes said she hopes the movement will empower more people to stand up for what they believe is right.

"Some people think the war is lost, but not really, because honestly bringing all these people together, we won," she said.

Morton County Sheriff Kyle Kirchmeier met with Phillips ahead of Thursday's walk to discuss safety. Kirchmeier said he supports the event as long as participants follow the guidelines he outlined, which include walking along the shoulder of the road and having vehicles leading and following the group.

"Hopefully they abide by the rules and we'll be good," Kirchmeier said.

While the prayer walk was on the Backwater Bridge, two highway patrol vehicles and a sheriff's deputy were parked up the hill, in a similar location to where law enforcement had been when the bridge was closed. Deputies plan to stay north of the walk area unless they need to respond to something in that area.

For much of Thursday's walk, participants blocked one lane of traffic, but people directed vehicles to drive around them.

Standing Rock historian LaDonna Brave Bull Allard, who spoke at the Cannon Ball Community Center ahead of the walk, said the opposition to Dakota Access has been a "long journey of awakening"

"Living on the reservation, sometimes we get into this idea that we are powerless," said Allard, who founded the Sacred Stone Camp, the first Dakota Access opposition camp. "From this last year, I learned that we have the power to change ourselves, we have the power to pray, we have the power to stand up. I truly believe if we continue to stand up in goodness and kindness and in prayer, we can do almost anything."