White House officials are seeking to stop the federal government’s top ethics officer from getting details about waivers granted to lobbyists and other appointees working in the administration, intensifying a power struggle between President Trump and the ethics agency.

Walter Shaub, director of the Office of Government Ethics, sent a memo in April to the White House and federal agencies asking for information about such waivers.

But in a May 17 letter, Mick Mulvaney, director of the Office of Management and Budget, questioned whether the Office of Government Ethics has legal jurisdiction to get information about waivers that have been granted. He said the Justice Department’s Office of Legal Counsel needed to be consulted.

“I therefore request that you stay the data call until these questions are resolved,” Mulvaney wrote Shaub in a letter first reported by the New York Times.

Shaub did not immediately respond to a request for comment.

But former OGE officials said the agency has clear authority to seek such documentation under the 1978 Ethics in Government Act. Without such reports, they said, it is impossible to know how many appointees have been granted exemptions from ethics rules – and how much leeway they have under the waivers.

“This is unprecedented interference with OGE,” said Don Fox, a former general counsel and acting director of the ethics office.

“The Ethics and Government Act was part of a whole package of post-Watergate legislation that had a common theme of transparency,” he added. “If there is nothing to hide, why hide it?”

OMB officials did not respond to requests for comment.

The tussle centers on OGE’s effort to determine whether the administration is complying with federal ethics regulations, including an executive order Trump signed in January that, among other measures, prohibits former lobbyists who join the government from participating in any matter they lobbied on for two years.