The Trump Administration sought to block former acting attorney-general Sally Yates from testifying in the House investigation of possible links between Russian officials and Donald Trump's campaign, according to letters provided to the Washington Post.
The effort to keep Yates from testifying has further angered Democrats, who have accused Republicans of trying to damage the inquiry.
According to the letters, the Justice Department notified Yates this month that the Administration considers her possible testimony - including on the firing of former national security adviser Michael Flynn for his contacts with the Russian ambassador - to be off-limits in a congressional hearing because the topics are covered by attorney-client privilege or the presidential communication privilege.
The issue of Yates' testimony adds to the political controversy surrounding the House Intelligence Committee's investigation of Russian meddling in last year's election and any possible coordination between Trump associates and Moscow.
David O'Neil, a lawyer for Yates, met at the Justice Department to discuss the issue with government officials last Friday.
At the meeting, O'Neil presented a letter in which he said the Justice Department had "advised" him that Yates' official communications on issues of interest to the House panel are "client confidences" that cannot be disclosed without written consent. O'Neil challenged that interpretation as "overbroad" in the letter.
The following day, in a letter to O'Neil, the Justice Department responded with another objection: that Yates's communications with the White House are probably covered by "presidential communications privilege," and referred him to the White House. A Justice Department spokeswoman declined to comment.
O'Neil then wrote to White House Counsel Donald McGahn, saying that he believed any privilege had been waived as a result of past White House statements and that Yates planned to testify unless he heard back from McGahn.
But that same day, the hearing, which also would have included former CIA director John Brennan and former director of national intelligence James Clapper, was cancelled by the House Intelligence Committee's chairman, Devin Nunes, and any White House decision on Yates's testimony became moot.
In his briefing yesterday, press secretary Sean Spicer said that the White House did not weigh in on whether Yates could testify. "To suggest in any way, shape or form that we stood in the way of that is 100 percent false," he said.
Nunes has said he cancelled the hearing to first hear from FBI Director James Comey in a classified setting. That session was also cancelled.
Democrats charge that Nunes has aligned himself too closely with the White House to conduct an independent probe.
"You see the unravelling of this committee happening overnight for no good reason," said Rep. Jackie Speier, a committee member. "We have a responsibility to do this investigation."