House Judiciary Committee Chairman Jerrold Nadler Jerrold (Jerry) Lewis NadlerDemocrats shoot down talk of expanding Supreme Court Schumer: 'Nothing is off the table' if GOP moves forward with Ginsburg replacement Top Democrats call for DOJ watchdog to probe Barr over possible 2020 election influence MORE (D-N.Y.) on Tuesday subpoenaed two former White House officials to testify before his committee and provide documents, a move that is likely to further exacerbate a standoff with the White House.

Nadler issued subpoenas to Annie Donaldson, who served as chief of staff to former White House counsel Don McGahn, and former White House communications director Hope Hicks Hope Charlotte HicksSenate intel leaders said Trump associates may have presented misleading testimony during Russia probe: report Cuomo turned down Trump invitation to participate in April press briefing: report Trump shakes up White House communications team MORE, one of President Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE's longest-serving aides in the West Wing.

The two subpoenas mark an ongoing fight between the White House and Congress as House Democrats seek to compel the testimony of other current and former administration officials as part of their sprawling investigations into Trump and his administration. ADVERTISEMENT

A representative for Donaldson's law firm did not immediately return a request for comment on Tuesday. Bob Trout, an attorney for Hicks, declined to comment.

The subpoena orders Hicks to provide documents by June 4 and then to testify before the Judiciary Committee on June 19.

A separate subpoena requires Donaldson to turn over a tranche of documents to the committee by June 4 and demands her appearance at a deposition on June 24.

Democrats believe Donaldson and Hicks witnessed a series of key events that they hope to examine as they review the episodes special counsel Robert Mueller Robert (Bob) MuellerCNN's Toobin warns McCabe is in 'perilous condition' with emboldened Trump CNN anchor rips Trump over Stone while evoking Clinton-Lynch tarmac meeting The Hill's 12:30 Report: New Hampshire fallout MORE examined as possible obstruction of justice.

Donaldson is said to have kept detailed notes about the meetings with McGahn that she sat in on and such notes were frequently mentioned in Mueller’s report. Hicks also played a pivotal role as a trusted adviser in Trump’s inner circle, following him from the early days of his presidential campaign and into the White House.

The Judiciary panel voted along party lines to authorize Nadler to issue subpoenas for Hicks, Donaldson, McGahn and former White House chief of staff Reince Priebus Reinhold (Reince) Richard PriebusLeaked audio shows Trump touted low Black voter turnout in 2016: report Meadows joins White House facing reelection challenges Trump names Mark Meadows as new chief of staff MORE in early April as part of its sprawling investigation into allegations of obstruction and abuses of power by Trump. At the same meeting, Democrats also voted to authorize Nadler to subpoena Mueller’s full report — an order he has already issued.

Nadler already issued a subpoena for documents and testimony from McGahn, but the former White House counsel has declined to comply with the requests at the direction of the White House.

The news of the subpoenas came the same day that McGahn evaded public testimony before the committee on instructions from Trump, who cited a Department of Justice legal opinion that McGahn is immune from compelled congressional testimony.