WASHINGTON (Reuters) - The top Democrat on the U.S. House Intelligence Committee said on Tuesday the panel should begin contempt proceedings if Steve Bannon, a former adviser to President Donald Trump, continues to refuse to testify in an investigation of Russia and the 2016 presidential election.

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U.S. Representative Adam Schiff said the House of Representatives committee’s subpoena remained in effect and Bannon’s interview has been rescheduled for next week.

“Testifying before the special counsel does not obviate Mr. Bannon’s obligations under the subpoena issued by the committee. Should Bannon maintain his refusal to return and testify fully to all questions, the committee should begin contempt proceedings to compel his testimony,” Schiff said in a statement.

Schiff said Bannon’s attorney informed the panel that the White House would not let him testify beyond 14 pre-approved yes-or-no questions.

Schiff said this “ban” on Bannon’s testimony covered issues between Trump’s election and inauguration, his time at the White House and communications with Trump since, even though Trump has not invoked executive privilege.

Committee Republicans said Bannon’s appearance was postponed at the committee’s initiative. “We look forward to having him before the committee once we can assure that he will be able to thoroughly answer all our questions without concerns regarding the scope of executive privilege,” Emily Hytha, a spokeswoman for Republican Representative Mike Conaway, who has helped oversee the committee’s Trump-Russia investigation, said in a statement.

The White House did not respond to a request for comment and neither did an attorney for Bannon.

Reuters reported on Monday that Bannon would not testify before the House committee on Tuesday, despite a subpoena requiring him to appear. The panel wants him to appear again to follow up on a Jan. 16 appearance that failed to satisfy some of its members.

A source familiar with the situation said Bannon was expected to appear before Special Counsel Robert Mueller next week and would answer all of Mueller’s questions.

House Intelligence is one of three congressional committees investigating Russia and the 2016 U.S. election, after U.S. intelligence agencies found that Russia attempted to influence the campaign on Trump’s behalf.

Moscow denies meddling in the presidential election, and Trump denies any collusion between his associates and Moscow.