Energy Secretary Rick Perry on Thursday became the latest Trump administration official to be subpoenaed in connection with the House impeachment inquiry, as a trio of House Democratic committee chairmen requested documents relating to Ukraine.

The House Intelligence, Foreign Affairs and Oversight Committees requested "key documents" from Perry by Oct. 18, the chairmen announced in a press release.

Department of Energy (DOE) Spokeswoman Shaylyn Hynes told Fox News, "The Department of Energy is aware of the House Committees’ letter to Secretary Perry and it is currently under review by DOE's Office of General Counsel."

Democrats have already subpoenaed Secretary of State Mike Pompeo, the Pentagon, the White House Office of Management and Budget and U.S. Ambassador to the European Union Gordon Sondland for documents as lawmakers probe a July 25 phone call between President Trump and his Ukrainian counterpart, Volodymyr Zelensky.

“Recently, public reports have raised questions about any role you may have played in conveying or reinforcing the president’s stark message to the Ukrainian president," Democratic Reps. Adam Schiff, Elijah Cummings and Eliot Engel said of Perry. “These reports have also raised significant questions about your efforts to press Ukrainian officials to change the management structure at a Ukrainian state-owned energy company to benefit individuals involved with Rudy Giuliani’s push to get Ukrainian officials to interfere in our 2020 election."

Two associates of Trump lawyer and confidant Rudy Giuliani who have been linked to his efforts to conduct investigations in Ukraine were indicted for campaign finance violations, according to court documents released Thursday. Lev Parnas and Igor Fruman are accused of using a limited liability company to make political contributions related to American elections, which violates Federal Election Commission (FEC) rules barring contributions from foreign nationals.

GIULIANI ASSOCIATES ARRESTED WHILE TRYING TO BOARD INTERNATIONAL FLIGHT WITH ONE-WAY TICKETS, PROSECUTORS SAY

The expanding impeachment probe was launched last month after an intelligence community member's whistleblower complaint raised concerns about the president's Ukraine phone call. In it, Trump asked Zelensky to probe onetime Vice President Joe Biden, his son Hunter and their business dealings in Ukraine. Joe Biden has for months been seen as the Democrats' frontrunner in the 2020 election against Trump.

Trump has denied abusing his position, saying the call was "perfect," and Zelensky said Thursday there was "no blackmail" during their call.

The whistleblower accused the president of "using the power of his office to solicit interference from a foreign country in the 2020 U.S. election," claiming Trump used $400 million in military aid, frozen in the days before that fateful phone call, to induce Zelensky to open a Biden inquiry.

Trump reportedly told House Republicans it was Perry who suggested he call Zelensky back in July, according to news outlet Axios.

RICK PERRY DENIES DISCUSSING BIDENS WITH TRUMP OR UKRAINE OFFICIALS: REPORTS

According to one source, Trump said something to the effect of: "Not a lot of people know this but, I didn't even want to make the call. The only reason I made the call was because Rick asked me to. Something about an LNG [liquified natural gas] plant," Axios reported, saying two other sources agreed with that recollection.

Perry denied ever mentioning the Bidens during discussions with Ukrainian officials or the president. On Friday he told the Christian Broadcasting Network in an exclusive interview that his dealings in Ukraine were part of the United States' effort to clean up corruption there.

President Trump has said Joe Biden's efforts to oust a Ukrainian prosecutor who was investigating the energy firm Burisma Holdings -- where Hunter Biden had held a board seat -- should be investigated for corruption.

On Monday, Perry denied rumors that he would resign at the end of November amid questions about his role in the controversy surrounding the now-infamous Trump-Zelensky call.

READ THE WHITE HOUSE LETTER

The White House issued an eight-page letter to House Speaker Nancy Pelosi, D-Calif., on Tuesday and said it wouldn't comply with the "illegitimate and unconstitutional" impeachment inquiry.

Fox News' John Roberts, Ronn Blitzer, Dom Calicchio, Louis Casiano and Charles Creitz contributed to this report.