The White House has directed former aides, Hope Hicks and Ann Donaldson, not to turn over documents to the House Judiciary Committee related to their time in the Trump administration.

The letters from the White House to the Judiciary panel are the latest effort by the White House to thwart congressional investigations into President Donald Trump. The president has vowed to fight “all of the subpoenas” as Democrats have launched multiple probes into his administration and personal financial affairs.

House Judiciary Chairman Jerrold Nadler (D-NY) issued subpoenas for Hicks, former White House communications director, and Donaldson, a former aide in the White House counsel’s office, last month.

The White House has claimed executive privilege over documents and testimony, invoking the power to keep information from the courts, Congress and the public to protect the confidentiality of the Oval Office decision-making process.

Nadler said in a statement Tuesday that, while the White House had instructed the former aides not to turn over materials, Hicks had agreed to turn over documents related to her time on Trump’s presidential campaign.

Nadler said he thanked Hicks for “that show of good faith.”

Asked whether the pair would be held in contempt if they refuse to turn over the outstanding documents, Nadler told reporters, “I would assume so.”

The White House has also directed former White House counsel Donald McGahn to refuse to provide documents or testify before the committee. The House is expected to vote to hold McGahn and Attorney General William Barr, who has refused to turn over the full Mueller report, in contempt of Congress next week.

The Associated Press contributed to this report.