"They appear to be succumbing to pressure from the administration," Schiff told ABC's "This Week."
ADVERTISEMENTHouse Intelligence Committee Chairman Adam Schiff, D-Calif., said Sunday that the National Security Agency is withholding "potentially relevant documents" from Congress regarding Ukraine just as President Donald Trump's Senate impeachment trial is set to start.
"The intelligence community is beginning to withhold documents from Congress on the issue of Ukraine," Schiff told ABC's "This Week." "They appear to be succumbing to pressure from the administration. The NSA in particular is withholding what are potentially relevant documents to our oversight responsibilities on Ukraine, but also withholding documents potentially relevant that the senators might want to see during the trial."
"That is deeply concerning," Schiff continued. "And there are signs that the CIA may be on the same tragic course. We are counting on the intelligence community not only to speak truth to power but to resist pressure from the administration to withhold information from Congress because the administration fears that they incriminate them."
Congressional Democrats have previously lamented the State Department and Pentagon's refusal to provide key documents related to Ukraine. The NSA and CIA did not immediately respond to requests for comment from NBC News.
Trump's impeachment trial is set to begin on Tuesday. Democrats and Republicans are still battling as to whether additional documents and witnesses will be presented at the trial — something that Senate Majority Leader Mitch McConnell, R-Ky., has said will be determined by a vote after the initial arguments are presented by both sides.
The two articles of impeachment charge the president with abusing his power by pushing for Ukraine to investigate former Vice President Joe Biden, his son Hunter Biden and Democrats while withholding nearly $400 million in military aid to the country as well as an official White House visit for Ukrainian President Volodymyr Zelenskiy and with obstructing Congress' efforts to probe his conduct.
Schiff on Sunday also addressed the recent Politico report in which multiple sources told the publication that the intelligence community is trying to persuade Congress to eliminate public testimony as part of the annual briefing on global security threats in light of Trump's public outburst last year at his top intelligence officials contradicting his beliefs.
Schiff on Thursday issued invitations to intelligence agency leaders to testify publicly and behind closed doors about the global threats.
"Well, you know, unfortunately, I think those reports are all too accurate," Schiff said. "The intelligence community is reluctant to have an open hearing, something that we had done every year prior to the Trump administration, because they're worried about angering the president."