President Trump is claiming executive privilege over special counsel Robert Mueller's entire report and the underlying documents, rendering an already tense relationship between the White House and Capitol Hill even more so. House Judiciary Committee Chairman Nadler had issued a subpoena for the full report, including redacted portions and supporting documents.

The news comes amid a House Judiciary Committee hearing to hold Attorney General William Barr in contempt of Congress, and as Mueller has been invited to testify before the committee.

Assistant Attorney General Stephen Boyd wrote Nadler a letter stating that because the committee rejected the Justice Department's request to delay the contempt hearing against Barr, negotiations over any accommodations would be terminated, and "the president has asserted executive privilege over the entirety of subpoenaed materials." It is, Boyd continued, a "protective assertion" of privilege intended to ensure President Trump's ability to "make a final decision whether to assert privilege following a full review of these materials."

White House press secretary Sarah Sanders described Nadler's demand as a "blatant abuse of power," and "unlawful and reckless."

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"Faced with Chairman Nadler's blatant abuse of power, and at the attorney general's request, the president has no other option than to make a protective assertion of executive privilege," Sanders said in a statement. "It is sad that Chairman Nadler is only interested in pandering to the press and pleasing his radical left constituency. The American people deserve a Congress that is focused on solving real problems like the crisis at the border, high prescription drug prices, our country's crumbling infrastructure, and so much more."

The decision could complicate the question of whether the administration could prevent Mueller from testifying on certain subjects.

Mr. Trump said Sunday he doesn't think Mueller should testify and has already said his White House is fighting "all the subpoenas" from Capitol Hill.

This is a developing story and will be updated.

Rebecca Kaplan contributed to this report.