(Reuters) - Protests against the Dakota Access Pipeline flared briefly for the first time since the federal government ruled against the project last month, law enforcement said on Wednesday, as five demonstrators were arrested and less-than-lethal rounds were fired by authorities.
The construction site of the $3.8 billion project had been the scene of fierce demonstrations by Native Americans and environmentalists for months. But in early December the U.S. Army Corps of Engineers denied a key easement needed to allow the pipeline to run under Lake Oahe, a reservoir formed by a dam on the Missouri River.
The Standing Rock Sioux, whose land is adjacent to the pipeline being built, asked protesters to disperse. Many of the thousands who joined the cause did, but some have remained, despite the harsh winter conditions in North Dakota.
Five people were arrested on Tuesday afternoon for trespassing after crossing the Cannonball River onto Army Corps land, the Morton County Sheriff's Department said in a statement on Wednesday.
Later in the evening, law enforcement said a group of around 100 protesters gathered on a bridge that was the site of previous demonstrations and police fired sponge rounds at people attempting to remove a "No Trespassing" sign.
"Actions by protesters yesterday are proving they are not willing to be peaceful, and are certainly not respectful of our mutual agreement," Morton County Sheriff Kyle Kirchmeier said in the statement.
Allison Renville, who was at the main protest camp Tuesday, said law enforcement were looking for confrontation, a criticism that both sides have leveled at each other.
"Morton County got it all wrong, people were coming with the intention of praying, but they are just ready to storm in and start a battle," she said.
Reporting by Timothy Mclaughlin in Chicago; Editing by Leslie Adler