CANNON BALL, N.D. — Officers in riot gear clashed again Wednesday with protesters near the Dakota Access pipeline, hitting dozens with pepper spray as they waded through waist-deep water in an attempt to reach property owned by the pipeline’s developer.

The confrontation came hours after North Dakota regulators criticized the pipeline company for not immediately reporting the discovery of American Indian artifacts and a day after President Barack Obama raised the possibility of future reroutes to alleviate tribal concerns.

Public Service Commission Chairwoman Julie Fedorchak said she was “extremely disappointed” that Texas-based Energy Transfer Partners waited 10 days before reporting last month’s discovery of stone cairns and other artifacts. The panel could decide to levy fines of up to $200,000, Fedorchak said, though she said such a high amount would be unlikely.

After an inspection, company consultants decided to divert the construction by about 50 feet, even though they determined there was a “low likelihood” any additional artifacts were buried nearby. The State Historic Preservation Office did concur with the company’s plan on how to proceed after the artifacts were found.

Although that change was relatively minor, Obama said it was possible the Army Corps of Engineers could eventually examine much larger ones that would reroute the pipeline in southern North Dakota to alleviate tribal concerns. He made the remarks during an interview Tuesday with the online news outlet NowThis.

On Wednesday afternoon, protesters tried to build a wooden pedestrian bridge across a creek to enter the property, then attempted to swim or boat across when officers dismantled the bridge, Morton County Sheriff’s spokeswoman Donnell Hushka said. Two arrests were reported.

Volunteer medics treated some of the protesters for hypothermia during the confrontation near the mouth of the Cannonball River.

About 140 people were arrested on the property last week in a law enforcement operation that cleared the encampment.

The potential for damage to American Indian sites and artifacts has been a flashpoint in a monthslong protest over the pipeline, which is intended to carry crude from western North Dakota almost 1,200 miles to a shipping point in Patoka, Illinois. The Standing Rock Sioux, whose reservation lies near the pipeline route, have led a protest over that issue and the pipeline’s potential hazard to drinking water.

Tribal officials said in September they had identified cultural artifacts on private land along the route. After that finding, North Dakota’s chief archaeologist, Paul Picha, inspected the area and said no sign of artifacts or human remains had been found.