Lawmakers want answers from the Pentagon and Justice Department on leaked classified documents surrounding the war in Ukraine, with several congressional committees demanding briefings from the Biden administration. 

Among other things, the leaked material includes warnings of weaknesses in Ukraine’s capabilities — specifically in air defense and shortfalls of ammunition as Kyiv prepares for a new counteroffensive — as well as bruising intelligence on allies, partners and adversaries alike. 

The Defense Department and the Department of Justice have said they will investigate the leak, which came in the middle of a two-week congressional recess, but lawmakers are expecting more information when they return to Capitol Hill next week, particularly on when intelligence agencies discovered the papers had made it online and how they responded. 

Senate Majority Leader Chuck Schumer (D-N.Y.) called for all senators to be briefed on the leak at some point after they return, a spokesman for the Democratic leader said on Tuesday. 

Senate Intelligence Committee Chairman Mark Warner (D-Va.) also on Tuesday said that he is “closely engaged” with top intelligence officials and “will continue to follow this situation closely.” 

“Any leak of classified information is extremely alarming,” Warner said in a statement. “As the Pentagon investigates this matter, Americans should remember that Russia has a long history of disinformation efforts and it would be wise to be wary of trusting any claims they see online relating to these documents.”

Sen. Mark Warner (D-Va.) addresses reporters following the weekly policy luncheon on Wednesday, March 22, 2023.

Later Tuesday, Warner told NBC News he had received a preliminary briefing but appeared frustrated on the answers he had received. 

“Finding out when the community discovered that these documents were gone, when they started to appear on the internet, even if it was in a remote site …  I expect to get those answers.” 

Across the Capitol, House Intelligence Committee Chairman Mike Turner (R-Ohio) told CBS News that he was briefed on the situation on Monday and that the case could amount to espionage.

“Obviously this is very detrimental … We don’t know what else might be coming or what else they have access to,” Turner told CBS on Monday. “That’s why it’s so important to find the source and to close down this source.”

“They’ve shown the extent to which the United States and Ukraine are aware of what Russia’s doing,” Turner added.

At least 100 documents began appearing online possibly as early as January on Discord and other chat forum sites. Last week, images of the papers spilled over to Twitter and Telegram and picked up attention. The material includes dozens of classified U.S. and NATO documents, some labeled “Top Secret.”

Pentagon spokesman Chris Meagher on Monday declined to discuss the veracity of the documents but allowed that the papers are similar in format to those used to provide daily updates to senior defense leaders on Ukraine- and Russia-related operations, as well as other intelligence updates. He warned that they “present a very serious risk to national security.” 

Still unknown to many is the scale and scope of the leak, who was responsible, how and why the information ended up online, what U.S. agencies were doing to scrub the information from websites and whether the administration would limit future intelligence to fewer people. 

The leak has also raised questions about how the United States will repair relationships with its allies who now may be wary of sharing information with Washington. 

Others want answers as to how U.S. intelligence agencies were seemingly not aware of the documents as they sat online for months. 

“These are things that we will find out as we continue to investigate,” Defense Secretary Lloyd Austin said when asked about the timeline on Tuesday, his first public remarks since the documents came to light. 

“They were somewhere in the web and where exactly and who had access at that point, we simply don’t know at this point,” he added.

Secretary of Defense Lloyd Austin answers questions during a House Subcommittee on Defense hearing on Thursday, March 23, 2023 to discuss the President’s FY 2024 budget. (Greg Nash)

The House and Senate Armed Services panels have also demanded answers from the administration. 

House Armed Services Committee Chairman Mike Rogers (R-Ala.) said in a statement that the reports of the intelligence leaks “are incredibly concerning,” and that the panel was “actively seeking answers from the Department of Defense.”

And a spokesperson for Senate Armed Services Committee Chairman Jack Reed (D-R.I.) said he is tracking the issue closely and has requested a briefing from the administration, though details were still up in the air. 

Reed “believes that breaches of U.S. national security and intelligence must always be addressed with the utmost seriousness and urgency. The Department of Defense and other agencies have launched investigations, and the Senate Armed Service Committee expects to be fully briefed on the Pentagon’s investigation as it proceeds,” they said.

The Pentagon said earlier this week that Austin became aware of the leak on April 6, while President Biden was informed of it late last week, according to the White House. 

On Tuesday, Austin would not comment on the Justice Department’s ongoing investigation but said the Pentagon takes the leak “very seriously.” 

“I will tell you that we take this very seriously, and we will continue to investigate and turn over every rock until we find the source of this and the extent of it,” he said.