National Security Adviser H.R. McMaster let one of his predecessors, Susan Rice, keep her top-secret security clearance nearly one month after reports surfaced about Rice's potential misuse of that clearance.

McMaster gave Rice, who served as former President Barack Obama's national security adviser, "unfettered and continuing access to classified information," and waived her "need-to-know" requirement on any documents she viewed during her tenure, Circa reported Thursday.

In early April, reports emerged that Rice on several occasions requested the identities of "masked" U.S. persons in intelligence reports linked to President Donald Trump's transition and campaign. The unmaskings have attracted criticism and scrutiny from congressional leaders, including Rep. Trey Gowdy (R., S.C.), chairman of the House Oversight Committee, who have sought more information on the matter.

Rice has maintained that she did nothing wrong.

"The allegation is that somehow the Obama administration officials utilized intelligence for political purposes. That's absolutely false," she told MSNBC in April.

McMaster's directive came in an undated, unclassified letter, sent to Rice's home in the last week of April.

Trump was not aware of the letter, several sources told Circa.

"I hereby waive the requirement that you must have a ‘need-to-know' to access any classified information contained in items you ‘originated, reviewed, signed, or received while serving,' as national security adviser," the letter said. "NSC will continue to work with you to ensure the appropriate security clearance documentation remains on file to allow you access to classified information."

Under federal law, it is common practice for certain senior officials to receive unfettered access to classified documents. But White House officials told Circa that, given the remaining suspicions around Rice, her access should have been curtailed or revoked until the end of the investigation.

"Basically, this letter which was signed in the last week of April undercuts the president's assertion that Susan Rice's unmasking activity was inappropriate. In essence, anybody who committed a violation as she did would not be given access to classified information," a senior West Wing official told Circa. "In fact, they would have their security clearance and right to ‘need-to-know' stripped."

However, McMaster wrote similar letters to all the living national security advisers from both Democratic and Republican administrations "as a matter of longstanding practice," according to the Weekly Standard.

A White House official told the Standard that revoking Rice's clearance would have been unusual and that this practice applies to other high level government officials, such as the secretary of state. The reason is "for the purposes of continuity," because it would be illegal for government officials to discuss certain sensitive information with a former official unless that official had a continued clearance.

The White House official noted that the process for reauthorizing a former official's security clearance is lengthy and that this security clearance does not give past officials like Rice "continued asking privileges for sensitive information."

Rice was not the only Obama administration official who regularly tried to unmask otherwise anonymous U.S. persons in intelligence reports. Former U.S. Ambassador to the United Nations Samantha Power unmasked "hundreds" in the last year of the Obama administration.

UPDATED Aug. 4, 9:24 A.M.: This post was updated to include information from the Weekly Standard on McMaster's letter.