Intelligence agencies warned the White House in 2019 that President Donald Trump‘s personal attorney Rudy Giuliani “was the target of an influence operation by Russian intelligence” designed to feed misinformation to the president, according to a report by The Washington Post published Thursday.

A former official told the Post that the intelligence community’s warnings prompted National Security Adviser Robert O’Brien to personally warn Trump that “any information Giuliani brought back from Ukraine should be considered contaminated by Russia.”

“Do what you want to do, but your friend Rudy has been worked by Russian assets in Ukraine,” the source said to the Post of O’Brien’s message.

Trump reportedly “shrugged his shoulders” and said “that’s Rudy” about the warning from O’Brien.

While Giuliani himself was not the subject of surveillance while traveling in Ukraine, some of his communications were retained since he was conversing with “suspected Russian assets.”

The warnings to the White House were “based on multiple sources, including intercepted communications, that showed Giuliani was interacting with people tied to Russian intelligence during a December 2019 trip to Ukraine, where he was gathering information that he thought would expose corrupt acts by former vice president Joe Biden and his son Hunter.”

Those warned about Russians targeting Giuliani include Attorney General William Barr, FBI Director Christopher Wray and White counsel Pat Cipollone, per the Post.