Meanwhile, Trump has insisted he has not been damaged by impeachment evidence detailing efforts by him and his administration to pressure Ukraine to publicly investigate his political rivals.
Speaking to reporters as he left on a campaign trip to Atlanta, the president said he was “not concerned about anything” that has been disclosed so far.
“It seems that nobody has any first-hand knowledge,” he said, adding: “Every one of those people cancelled themselves out.”
His comments came a day after the release of an impeachment inquiry transcript in which career State Department official George Kent said Mr Trump wanted to hear just three words from the Ukraine president in their July phone call: Investigations, Biden, Clinton, PA Media reports.
Kent told investigators that was his understanding of what Mr Trump wanted Ukrainian President Volodymyr Zelenskiy to say to unlock US military aid, as relayed to the official by others, including those in direct contact with the president.