Rep. Mike Quigley (D-Ill.), a member of the House Intelligence Committee, said Monday that President Trump's personal attorney Rudy Giuliani could be held in inherent contempt if he defies a subpoena sent by Democrats on Monday.

"We're bound by the rules," Quigley said when asked by MSNBC host Katy Tur about how Democrats, who have launched an official impeachment inquiry into President Trump, would react to Giuliani refusing to comply with the subpoena.

"How the strategy moves forward - going forward on a criminal basis, a civil basis - you know I've heard people talk about bringing back inherent contempt. I think at this point the House would be willing to go forward with inherent contempt at least in terms of fining people."

Quigley called inherent contempt as "one of the few powers that the House actually has."

"In this case we can actually fine" those who don't obey congressional requests, he added.

The chairmen of the House Intelligence, Oversight and Foreign Affairs committees earlier Monday asked Giuliani to hand over by Oct. 15 documents related to the ongoing Ukraine controversy as part of the House's impeachment inquiry.

"Your failure or refusal to comply with the subpoena, including at the direction or behest of the president or the White House, shall constitute evidence of obstruction of the House's impeachment inquiry and may be used as an adverse inference against you and the president," the chairmen warned in a letter to the president's personal attorney.

Giuliani has emerged as a key figure in the ongoing controversy over Trump asking Ukrainian President Volodymyr Zelensky to investigate former Vice President Joe Biden and his son Hunter during a July 25 phone call.

Giuliani's name comes up several times in the intelligence community whistleblower report that brought scrutiny to the call, and his involvement has been a cause for concern among officials who feel he was conducting shadow diplomacy as a private citizen.

In a tweet Monday evening, Giuliani wouldn't say whether he would comply with the subpoena.

"I have received a subpoena signed only by Democrat Chairs who have prejudged this case," he said.