US Representative Adam Schiff, one of Joe Biden’s key allies in Congress, has acknowledged that classified documents discovered at properties linked to the president may have compromised US national security.

“I don't think we can exclude the possibility without knowing more of the facts,” Schiff said on Sunday in an ABC News interview. The California Democrat stressed that the House Intelligence Committee should receive briefings from US intelligence agencies on both the Biden documents and the classified papers recovered in an FBI raid last August at former President Donald Trump’s Mar-a-Lago resort in Florida.

“We have asked for an assessment in the intelligence community of the Mar-a-Lago documents,” Schiff said. “I think we ought to get that same assessment of the documents found in the think tank as well as the home of President Biden. I’d like to know what these documents were. I’d like to know what the [intelligence community's] assessment is, whether there was any risk of exposure and what the harm would be and whether any mitigation needs to be done.”

At issue are classified documents, some marked “top secret,” from Biden’s two terms as vice president in 2009-2017. CBS News reported last Tuesday that lawyers for the president found classified documents in his office at the Penn Biden Center, a Washington think tank. Two days later, the White House confirmed that additional secret documents were discovered at two locations in Biden’s Delaware home, including his garage. Also on Thursday, still more classified papers were found in Biden’s home.

Attorney General Merrick Garland appointed a special counsel to investigate the apparent mishandling of documents. Schiff said Garland had little choice after appointing an outside investigator in the case involving Trump.

“I still would like to see Congress do its own assessment, and receive an assessment from the intelligence community of whether there was exposure to others of these documents, whether there was harm to national security in the case of either set of documents with either president,” Schiff said.

The first batch of Biden documents was discovered at the Penn Biden Center on November 2, a week before the midterm congressional elections. Asked whether Biden’s administration should have been more forthcoming, rather than hiding the news for more than two months, Schiff said he would reserve judgment. Republicans won control of the US House in the midterms, meaning Schiff lost his position as chairman of the intelligence committee.