The chairman of the House Intelligence Committee has accused US intelligence agencies of withholding documents from Congress on Ukraine that could be significant to president Donald Trump’s impeachment trial.

“They appear to be succumbing to pressure from the administration,” Representative Adam Schiff said on ABC’s This Week.

Mr Schiff was selected by House Speaker Nancy Pelosi as the lead impeachment manager for Mr Trump’s Senate trial.

He contended the National Security Agency “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”.

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Donald Trump’s impeachment trial resumes on Tuesday (Jonathan Brady/PA)

Mr Schiff also said “there are signs that the CIA may be on the same tragic course”.

The NSA and CIA did not immediately respond to a requests for comment.

Mr Trump’s impeachment trial resumes on Tuesday.

Democrats have previously criticised the State Department for withholding relevant documents to the impeachment inquiry.

In the weeks since Mr Trump was impeached, Democrats have sought to focus on new evidence about his effort to pressure Ukraine to investigate his political rivals and are pushing the Senate to consider new documents and testimony, such as from former national security adviser John Bolton.

During the ABC interview, Mr Schiff was asked about a Politico report that said intelligence officials were pushing the House and Senate Intelligence committees to drop the public portion of an annual briefing on world security threats following last year’s session in which Mr Trump lashed out over the assessments on North Korea, Iran and the Islamic State.

The request was reportedly being made in a bid to avoid a repeat in which intelligence officials might publicly disagree with Mr Trump on the security risks.

“Perhaps Intelligence should go back to school!” Trump tweeted after that January 29 hearing, before abruptly reversing course and saying he and the intelligence community “are all on the same page”.

On Sunday, Schiff described the news reports as “all too accurate”.

“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,” he said.