Washington (CNN) The Office of the Director of National Intelligence, led by acting director Joseph Maguire, has refused to comply with a deadline to hand over a whistleblower complaint to the House Permanent Select Committee on Intelligence that had been deemed by the intelligence community inspector general to be "credible and urgent."

Tuesday night, the Office of the Director of National Intelligence sent letters to committee Chairman Adam Schiff, a California Democrat, and ranking Republican Devin Nunes of California, saying the complaint "does not meet the definition of 'urgent concern' because it does not relate to 'intelligence activity.' "

The complaint "involves confidential and potentially privileged matters relating to the interests of other stakeholders within the Executive Branch," a copy of the letter, obtained by CNN , says, adding that complying with the committee's requests "will necessarily require appropriate consultations."

In the letter, the Office of the Director of National Intelligence reveals that the complaint does not involve anyone in the intelligence community but rather "stakeholders within the Executive Branch." As a result, its lawyer argues, the complaint is not of "urgent concern" to them.

The office says it plans to work with the House intelligence Committee but given that executive branch members are involved, there are "confidential and potentially privileged matters" that "will necessarily require appropriate consultations."

Maguire won't appear at Thursday hearing

Schiff's subpoena was issued Friday evening, and the national intelligence director's office says that wasn't enough time to comply. Maguire will also not appear at a scheduled congressional hearing on Thursday; his office says he "is not available on such short notice."

In response, Schiff said: "The IC IG determined that the complaint is both credible and urgent, which is why the Committee must move quickly. The Committee's position is clear -- the Acting DNI can either provide the complaint as required under the law, or he will be required to come before the Committee to tell the public why he is not following the clear letter of the law, including whether the White House or the Attorney General are directing him to do so. He has yet to provide the complaint in response to the Committee's subpoena, so I expect him to appear on Thursday, under subpoena if necessary."

Schiff said on CNN's "Anderson Cooper 360" on Monday night that he had issued a subpoena to Maguire after the intelligence community inspector general found the complaint to be "credible" and of "urgent concern," conditions that, he argues, require congressional notification.

Specifically, Schiff is demanding that Maguire turn over the intelligence community inspector general's "determination and all records pertaining to the Office of the Director of National Intelligence's (ODNI) involvement in this matter, including any and all correspondence with other Executive Branch actors such as the White House," according to last week's news release from the congressman's office.

Schiff has argued that the acting director of national intelligence has already taken unprecedented steps to withhold the complaint from Congress.

"A Director of National Intelligence has never prevented a properly submitted whistleblower complaint that the IC IG determined to be credible and urgent from being provided to the congressional intelligence committees. Never. This raises serious concerns about whether White House, Department of Justice or other executive branch officials are trying to prevent a legitimate whistleblower complaint from reaching its intended recipient, the Congress, in order to cover up serious misconduct," he wrote in a statement released last week.

Schiff also argued that Maguire had acted outside the authority of his post by consulting with the Department of Justice about the complaint as he involved "another entity within the Executive Branch in the handling of a whistleblower complaint.

Legal experts say the relevant legal statute has long been a point of contention between the executive and legislative branches.

"The Executive Branch -- in both Republican and Democratic administrations -- has consistently taken the view that it has the right to control whether and how Congress receives classified or otherwise privileged information from the Executive Branch and its employees, even when those employees are whistleblowers whose complaints are made under statutory authority," said Jamil N. Jaffer, the founder and executive director of the National Security Institute at George Mason University's Antonin Scalia Law School.

"At the same time, Congress has long taken the view that its independent constitutional oversight and other authorities, including the authority to legislate and appropriate funds, requires it to have access to all types of classified and otherwise privileged information and that it can authorize whistleblowers to provide information directly to Congress under certain circumstances, as the relevant statute permits," he added.

Schiff said Monday that he does not know the exact nature of the complaint, as he has not yet received the details from the Office of the Director of National Intelligence, nor the identity of the whistleblower.

He declined to say whether he has been contacted by the whistleblower or their legal representation, saying he wouldn't want to jeopardize them.

Limited options

The whistleblower, however, is presumably aware of details related to the complaint and a source familiar with the situation told CNN on Tuesday that legal counsel for the unknown individual is discussing next steps.

However, the options appear to be limited.

A source familiar with the case told CNN that the Intelligence Community Whistleblowers Protection Act likely only offers one real path forward: circumventing the Office of the Director of National Intelligence and giving the complaint directly to the committee.

That route may also be complicated, the source warned, noting it could raise classification issues tied to transmitting the material.

"At the end of the day, because the relevant statute doesn't clearly permit the whistleblower to go directly to Congress in the exact circumstances in play here -- although there are arguments he or she might make -- this is likely to come down to a battle between the legislative and executive branches, and likely will result in another subpoena, another contempt proceeding and then more litigation in the courts that could go on for years," said Jaffer, who also served as senior counsel for the House Permanent Select Committee on Intelligence.

"Because the courts are likely to take a long time to act, and may actually decline to get involved due to the political nature of the dispute and the potential national security issues in play, Congress is likely to be left to other fairly limited tools to force the President and his team to do what it wants, including applying public pressure, threatening to hold up acting DNI Maguire's confirmation as DNI, threatening to impeach Maguire and cutting off funding the administration wants," he told CNN.