WASHINGTON (AP) — A congressional oversight committee on Thursday said the Justice Department is "obstructing" its investigation into former President Donald Trump's handling of White House records by preventing the release of information from the National Archives.

The House Committee on Oversight and Reform sent a letter to Attorney General Merrick Garland accusing the Justice Department of impeding the panel's expanded investigation into the 15 boxes of White House records that Trump took to his Mar-a-Lago residence in Florida after leaving office last year. The Archives in February revealed it had found classified material in the boxes and referred the matter to the Justice Department.

The letter from Rep. Carolyn Maloney, D-N.Y., the chairwoman of the Oversight Committee, outlines communications between the committee and the National Archives that took place between February to late March.

In those letters, Maloney made a series of requests for information she said the committee needs to determine if Trump violated federal records laws over his handling of sensitive and even classified information. In response, the general counsel for the archivist wrote on March 28 that "based on our consultation with the Department of Justice, we are unable to provide any comment."

"By blocking NARA from producing the documents requested by the Committee, the Department is obstructing the Committee's investigation," Maloney wrote in the letter released Thursday.

Maloney added that while the committee is not looking to interfere with the department's ongoing investigation, lawmakers have not received any explanation as to why the department is preventing the archivist from providing information about the contents of the boxes.

The House's oversight panel has repeatedly cited its authority to investigate matters involving the Presidential Records Act, which was enacted in 1978 after former President Richard Nixon wanted to destroy documents related to the Watergate scandal.

Maloney had warned in December 2020 that she had "grave concerns" that the Trump administration was not complying with the federal records act, even writing in a letter to the archivist citing those concerns that the departing administration "may not be adequately preserving records and may be disposing of them."

While federal law bars the removal of classified documents to unauthorized locations, it is possible that in this case, Trump could try to argue that, as president, he was the ultimate declassification authority.

The former president has denied reports of tensions with the National Archives and his lawyers have said that "they are continuing to search for additional presidential records that belong to the National Archives."

The attorney general has acknowledged that the department received the referral from the Archives, but it is longstanding Justice Department policy not to comment on investigations.

Democrats and Republicans on Capitol Hill may face a long wait for answers to their questions about specific investigations.

Generally, under Justice Department guidelines, details of investigations are supposed to remain out of the public view until charges are filed or warrants are filed. And, if grand juries are convened, the Justice Department is precluded under federal law from discussing specifics of a grand jury investigation before an indictment is handed down.

Garland has also made clear to prosecutors that the Justice Department won't be influenced by outside political pressure.

The Oversight Committee asked Garland to respond by next week with either a green light for the National Archives to cooperate with their request or provide an explanation as to why the department is imposing such limitations.