Officials said notes about calls to leaders including Russia’s Vladimir Putin and the Saudi crown prince had not been handled in the usual way.
They say aides severely curtailed who saw them in a bid to stop leaks.
The White House has not so far commented on the claims, which follow the start of an impeachment inquiry.
Democrats launched the inquiry after the transcript of a July phone call revealed that President Trump pushed Ukraine’s President VOLODYMYR ZELENSKY to investigate Democratic presidential candidate Joe Biden.
On Friday the White House confirmed that the transcript had been placed in a separate system for highly classified information.
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