Energy Secretary Rick Perry is planning to step down from his position by the end of November.

Perry’s recent travels to Ukraine have entangled him in the impeachment inquiry into President Donald Trump, though two sources told Politico the impeachment inquiry is unrelated to his resignation.

Sen. Bob Menendez (D-New Jersey) sent a letter to Perry asking about his interactions in Ukraine. Perry has raised some eyebrows after he replaced Vice President Mike Pence in leading the U.S. delegation to the inauguration of Ukrainian president Volodymyr Zelensky in May.

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“Given your role as the leader of the official United States delegation to the inauguration, and the White House’s recent release of evidence that President Trump requested that Ukraine’s government investigate his domestic political opponent, your insight into the U.S. delegation’s trip is of particular interest to the Senate Foreign Relations Committee,” wrote Menendez.

Trump is currently under fire for reportedly threatening to withhold aid from Ukraine unless the government agreed to investigate democratic presidential candidate Joe Biden.

The White House and Department of Energy did not confirm Perry plans to resign.

“While the Beltway media has breathlessly reported on rumors of Secretary Perry’s departure for months, he is still the Secretary of Energy and a proud member of President Trump’s Cabinet. One day the media will be right. Today is not that day,” DOE spokesperson Shaylyn Hynes said.

Deputy Energy Secretary Dan Brouillette is expected to replace Perry.

Joe McMonigle, a former DOE chief of staff told the Washington Examiner that Brouillette would often substitute for Perry at cabinet meetings while Perry traveled internationally to promote oil and gas deals.

“He knows how to work the department from all angles and is an effective manager,” McMonigle said. “Dan is really not going to miss a beat.”

Perry plans to cooperate with the House investigation.

“I’ll just briefly say we’re going to work with Congress and answer all their questions,” he said at a department event on artificial intelligence and energy.