Washington (CNN) The Justice Department's inspector general did not find any evidence that the FBI had tried to put undercover agents or informants inside Donald Trump's 2016 presidential campaign, people familiar with a draft of the inspector general's report told The New York Times.

Trump and his supporters have alleged without evidence that the FBI spied on his campaign and that former President Barack Obama ordered Trump's phones tapped . The finding by the inspector general, Michael E. Horowitz, is expected to undercut Trump's claim that the FBI acted improperly while investigating several Trump associates starting in 2016, the Times reports.

President Donald Trump looks to the crowd as he speaks at a campaign rally in Sunrise, Fla, Tuesday, Nov. 26, 2019. (AP Photo/Susan Walsh)

Horowitz found that leaders at the FBI were not politically motivated in pursuing a secret wiretap on former Trump campaign adviser Carter Page, according to the newspaper. His findings are part of a review of the FBI's effort to obtain warrants under the Foreign Intelligence Surveillance Act on Page.

But the inspector general is also expected to sharply criticize FBI leaders in some ways for their handling of the investigation.

Horowitz concluded the FBI was careless and unprofessional in pursuing the Page wiretap, according to the Times. He is expected to detail omissions and errors from when FBI officials applied for the wiretap, people familiar with a draft of the report told the Times.

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