President Biden on Tuesday said he is unaware of what documents from his time as vice president were discovered at a former private office of his, adding that he was surprised such records were kept there.

“I was briefed about this discovery and surprised to learn that there were any government records that were taken there to that office. But I don’t know what’s in the documents. My lawyers have not suggested I ask what documents they were,” Biden said when asked during the North American Leaders’ summit in Mexico.

It was the first time since the discovery was reported on Monday night that Biden addressed the matter. 

Biden’s special counsel confirmed in a statement after reports surfaced that the White House was cooperating with the Justice Department regarding a review of documents found in a University of Pennsylvania office in Washington that once belonged to Biden between his time as vice president and his 2020 presidential campaign.

“People know I take classified documents, classified information seriously. When my lawyers were clearing out my office at the University of Pennsylvania…they found some documents in a box in a locked cabinet, or at least a closet. And as soon as they did, they realized there were several classified documents in that box and they did what they should have done,” Biden said.

“They immediately called the Archives, immediately called the Archives, turned them over to the Archives,” he added.

“I’ve turned over the boxes, they’ve turned over the boxes to the Archives. And we’re cooperating fully, cooperating fully with the review, which I hope will be finished soon. And there’ll be more detail at that time,” Biden said.

Attorneys for Biden discovered the documents in November, days before the crucial midterm elections and the items were turned over to the agency the next day. The discovery of the documents was first reported by CBS News.

The president and vice president are required under the Presidential Records Act to turn over documents to the National Archives for secure storage.

The revelation immediately drew comparisons to an FBI search of former President Trump’s Mar-a-Lago property in which federal investigators seized classified documents there as part of a wider federal probe into potential mishandling of the information. 

The reports of classified documents discovered in an office once held by Biden energized the new House Republican majority, who were already preparing to launch a host of investigations into the Biden administration.