At least four national security officials raised concerns about Trump's relations with Ukraine before and after his July 25 call with the Ukrainian president, The Washington Post reports. Officials initially expressed concerns about the removal of U.S. ambassador to Ukraine Marie Yovanovitch in May, and were reportedly “baffled and alarmed” by the behavior of Trump's personal attorney Rudy Giuliani—who had pushed for Yovanovitch's removal. Officials also spoke up when U.S. ambassador to the European Union, Gordon Sondland, claimed that he had been put in charge of Ukraine relations by Trump. Sondland also reportedly stated in a meeting that dropped investigations in Ukraine “need to be started up again,” which many understood to be a reference to corruption probes into former Vice President Joe Biden and his son.

Minutes after Trump's call with Ukrainian president Volodymyr Zelensky—where he pushed for Ukraine to probe Biden—National Security Council officials were pinging superiors about their concerns, according to the Post. The call's transcript was moved to the White House's highly classified network hours after the call ended. Concerns were reportedly shared with NSC legal adviser John Eisenberg, then-acting deputy national security adviser Charles Kupperman, and former national security adviser John Bolton. Trump reportedly ordered the amount of NSC members to be cut after a whistleblower filed a complaint about Trump's call with Zelensky.