BISMARCK, N.D. — The federal government is contesting North Dakota's claims that the state should be reimbursed for the $38 million the state spent policing prolonged protests against the Dakota Access oil pipeline.

The Army Corps of Engineers filed a motion Tuesday asking a federal judge to dismiss the state's lawsuit seeking to recoup the costs, arguing it has "limited authority to enforce its rules and regulations" on land it manages.

"The federal government acquired the Corps-managed land ... without accepting any special criminal jurisdiction over this property," the agency said in court documents. "Thus, North Dakota has the authority and responsibility to enforce criminal law on the Corps-managed lands..."

North Dakota Attorney General Wayne Stenejem called the Corps' claim that it is "toothless" in enforcing law on its land "preposterous."

Stenehjem filed the claim in Bismarck federal court in July after the agency ignored an administrative claim he filed a year earlier.

Thousands of opponents of the $3.8 billion pipeline that's been moving oil from the Dakotas through Iowa to Illinois for more two years gathered in southern North Dakota in 2016 and early 2017, camping on federal land and often clashing with police, resulting in 761 arrests over six months.

The Standing Rock Sioux Tribe opposed the pipeline built by Texas-based Energy Transfer Partners over fears it would harm cultural sites and the tribe's Missouri River water supply — claims rejected by the company and the state.

Stenehjem has said the Corps "allowed and sometimes encouraged" protesters to illegally camp without a federal permit. The Corps has said protesters weren't evicted due to free speech reasons.

The agency said in court papers it used discretion, calling the federal government's relationship with the Indian tribes "contentious and tragic."

The Corps said its "enforcement decisions" occurred in the "context of this complex and contentious history."

The pipeline construction began while Barack Obama was in the White House. President Donald Trump just days after taking office in January 2017 pushed through completion of the stalled project.

The company announced plans this year to double the pipeline's capacity.

Trump last year denied a state-requested disaster declaration to cover the state's costs. The Justice Department later gave the state a $10 million grant for policing-related bills. The pipeline developer gave the state $15 million to help with the costs that were funded from loans from the state-owned Bank of North Dakota.

Stenehjem has said the $25 million the state has received to offset the costs doesn't get the Corps off the hook for the state's $38 million total cost.