In this file photo Lawyer of the US president Rudy Giuliani looks on before the US president announces his Supreme Court nominee in the East Room of the White House on July 9, 2018 in Washington, DC.

The House Intelligence Committee has subpoenaed President Donald Trump's personal attorney Rudy Giuliani for documents as part of its impeachment inquiry into the president.

In a letter to Giuliani dated Monday, the heads of three House committees asked for information related to the president's and his lawyer's efforts to get Ukraine's government to investigate the Biden family.

Three Democratic-led panels — the Intelligence, Oversight and Foreign Affairs committees — are demanding that Giuliani produce all text messages, phone records and other communications related to the "scheme" he is accused of perpetrating "in order to determine the full extent of this effort by the President and his Administration to press Ukraine to interfere in our 2020 presidential election."

They wrote that the House Democrats' probe "includes an investigation of credible allegations that [Giuliani] acted as an agent of the President in a scheme to advance his personal political interests by abusing the power of the Office of the President." Reps. Adam Schiff, D-Calif., Elijah Cummings, D-Md., and Eliot Engel, D-N.Y. — who lead the Intelligence, Oversight and Foreign Affairs committees, respectively — asked him to produce documents by Oct. 15.

Spokespeople for Giuliani and the White House did not immediately respond to CNBC's requests for comment. Giuliani has suggested he may not comply with committee requests. On Sunday, he told ABC that he "wouldn't cooperate" with Schiff as long as he leads the panel.

The subpoena adds to the heightened scrutiny of both administration officials and outside Trump confidants after the House decided last week to move forward with impeachment proceedings. On Friday, the Intelligence Committee subpoenaed Secretary of State Mike Pompeo for documents. The heads of the Appropriations and Budget committees also asked Friday for records related to the Office of Management and Budget's involvement in the Trump administration deciding to hold back nearly $400 million in military aid to Ukraine.