Acting Director of National Intelligence Joseph Maguire will testify before the House Intelligence Committee on Sept. 26, after Chairman Adam Schiff accused his office of withholding an intelligence community's whistleblower complaint from Congress.
Schiff, D-Calif., issued a subpoena last week for the complaint, described as "urgent" by the intelligence community's inspector general.
(MORE: Trump announces his pick for DNI Rep. John Ratcliffe dropped from consideration)The chairman said Wednesday that Intelligence Community Inspector General Michael Atkinson would brief the committee behind closed doors on Thursday morning regarding the handling of the complaint, but likely not the content. Next Thursday's hearing with Maguire will be public.
"The director has said essentially that he is answering to a higher authority and refusing to turn over the whistleblower complaint. This is deeply troubling," Schiff said on CBS's "Face the Nation" on Sunday.
"Ignoring the subpoena, ignoring our request. No DNI -- no director of national intelligence -- has ever refused to turn over a whistleblower complaint."
A spokesperson for the DNI did not immediately respond to requests for comment.
The complaint involves conduct by someone outside the intelligence community, according to a letter to Schiff from Jason Klitenic, general counsel for the Office of the Director of National Intelligence, obtained by ABC News.
(MORE: Trump's pick for intelligence director misrepresented role in anti-terror case)According to the letter, "The complaint here involves confidential and potentially privileged matters relating to the interests of other stakeholders within the Executive Branch."
The letter was first obtained by The New York Times on Tuesday.
Klitenic also argued that the complaint doesn't meet the definition of "urgent concern" that would require the DNI to forward the matter to Congress, according to the Times.
ABC News' James Meek and Alex Mallin contributed to this report.