(The Hill) — The Justice Department seized at least 700 pages of classified materials when it first recovered documents from former President Donald Trump’s Florida home in January, according to a letter released by the National Archives on Tuesday.

An exchange between the custodians for presidential records and Trump’s attorneys, released after it was first obtained by a conservative news outlet, indicates the former president’s legal team spent months attempting to block the FBI and the intelligence community from reviewing the documents to assess the potential national security fallout.

It also reveals that among the materials were those at “the highest levels of classification, including Special Access Program (SAP) materials.”

The May letter from Archives also reiterates a warning first relayed by the Justice Department (DOJ) the month before.

“Access to the materials is not only necessary for purposes of our ongoing criminal investigation, but the Executive Branch must also conduct an assessment of the potential damage resulting from the apparent manner in which these materials were stored and transported and take any necessary remedial steps,” Debra Steidel Wall, acting archivist of the United States, wrote in relaying a message from DOJ’s National Security Division.