WASHINGTON — House Republicans have summoned the head of the independent federal ethics office to answer questions about his agency and his public criticism of President-elect Donald Trump's plan to separate from his real estate empire.

A letter sent late Thursday from Rep. Jason Chaffetz, R-Utah, chairman of the GOP-led House Oversight and Government Reform Committee, was viewed by ethics experts as a veiled threat to the budget of the Office of Government Ethics unless its director changes his rhetoric and approach.

The letter to Walter Shaub, director of the Office of Government Ethics, asks him to appear before lawmakers in a closed-door, transcribed interview. Shaub is not being subpoenaed, but was asked to respond to questions in a setting much like a deposition, committee staff said.

The chairman said he has not yet decided whether to ask Shaub to testify at a public committee hearing but will wait for the transcribed interview, which was first reported on by the Wall Street Journal.

Chaffetz's letter was condemned early Friday by Sen. Charles Schumer, D-N.Y., the Senate minority leader.

"Mr. Chaffetz's attempt to intimidate the office is deplorable, and would be a distraction that would make it harder for OGE [Office of Government Ethics] to do it's already difficult job," Schumer said in a prepared statement. "It is totally out of line when Americans want clean and accountable government. Mr. Chaffetz should instead focus on his job and let Mr. Shaub and OGE focus on theirs."

Rep. Elijah Cummings, D-Md., the top Democrat on the Oversight Committee, has called for a public hearing on Trump's potential conflicts of interest featuring Schaub. He blasted Chaffetz's letter Friday.

"The Oversight Committee has not held one hearing, conducted one interview, or obtained one document about [Trump]'s massive global entanglements, yet it is now apparently rushing to launch an investigation of the key government official for warning against the risks caused by [Trump]'s current plans," Cummings said. "Rather than acting as a cheerleader for Donald Trump and attacking or intimidating his critics, the Committee should do its job under the Constitution and investigate his sprawling business deals around the world."

Ethics experts assailed Chaffetz's letter as a partisan attack on Shaub for doing his job.

Richard Painter, who served as ethics adviser to former president George W. Bush, called the letter a "clear threat to pull the funding of the Office of Government Ethics" unless the agency follows the wishes of Trump and the Republican leadership.

"They are saying lay off Trump and push through these nominees or we'll kill the funding of OGE," Painter said. He and other ethics lawyers from both parties said the agency plays an important role, and killing it or reducing its authority would be a blow to avoiding conflicts of interest in a new administration and enforcing basic standards of ethics and transparency.

Shaub, appointed by President Barack Obama to a five-year term that has a year to go, gave an extraordinary public admonishment on Wednesday of Trump's plan to place his businesses in a trust managed by his elder sons. The ethics chief said the plan was "wholly inadequate" to protect the incoming president from conflicts of interest.

"Stepping back from running his business is meaningless from a conflict-of-interest perspective," Shaub said at a forum at the Brookings Institution.

The comments followed a tweetstorm from Shaub's office in late November that congratulated Trump on divesting himself of his business holdings. The tweets were composed, public records requests have revealed, by Shaub himself. Trump had not agreed to divest, however.

Before Senate confirmation hearings began this week on Trump's cabinet, Shaub accused Republicans of trying to rush through some Cabinet nominees whose financial disclosure documents had not been vetted by his staff.

In his letter, a copy of which was obtained by the Post, Chaffetz told Shaub, "Your agency's mission is to provide clear ethics guidance, not engage in public relations."

The letter noted that the ethics office is up for congressional reauthorization.

"The Committee is thus continuing its examination of OGE's operations," Chaffetz wrote. "[The office's] statutory authorization lapsed at the end of fiscal year 2007 and the Committee has jurisdiction in the House of Representatives for reauthorizing the office."

Chaffetz said in an interview that after the election, he asked Shaub to meet with him to discuss the tweets and other operations of the ethics office. But the congressman said Shaub refused to meet.

OGE spokesman Vincent Salamone declined to comment early Thursday when asked about Chaffetz's claim. Salamone could not immediately be reached for comment later on the committee's request for a transcribed interview.