Interior Department says it will temporarily block Democratic aides from official oversight trips

"The Department of the Interior will not be funding any travel for House Appropriation staff until the ethics issue with their staff is resolved by Chairwoman (Betty) McCollum and the Committee and the assurance is made that all our employees will be treated equally, fairly and respectfully," an Interior Department spokeswoman told CNN.

The spokeswoman did not comment on what directly led to the fallout between the two bodies.

NBC News, which first reported the spat, reported late Wednesday it involved a "complaint over staff behavior" involving an Interior Department employee who attended an oversight trip.

Because Congress controls budgets of every agency through the appropriations committees, congressional staff can take trips to oversee any aspect of agency work. Based on a 1953 law, the agency is required to pay for those trips as a part of Congress oversight work.

The spokeswoman for the department told CNN the department's chief of staff reached out to the appropriations committee about the issue, but did not receive a response.

Evan Hollander, a spokesman for the House Appropriations Committee, told CNN that "senior staff at Interior have concocted this entire incident to obstruct the House's critical oversight work."

"Fabricating a story to block Congressional oversight is another example of the Trump administration's trampling of democratic norms. Congressional Democrats will not stand for this illegal and outrageous conduct," Hollander said.

McCollum's spokesman did not immediately respond to a request for comment.

The committee, which is controlled by Democrats, and department leadership have been at odds over Interior Secretary David Bernhardt's plan to move the Washington, DC, headquarters of the Bureau of Land Management to Colorado and shift hundreds of positions to the western US.

The effort has faced opposition from current and former Washington, DC-based BLM employees, who say it will weaken the bureau's efficiency and influence. BLM argues the headquarters move will place staffers closer to the lands and people they work with

Bernhardt said recently that plan is moving forward after a 30-day period for congressional notification was completed. Democrats on the committee objected to the plan and said the Department did not fully answer their questions.