According to the document, the investigation did not find any evidence of collusion between Russian Federation and Trump's campaign team.
Democrats have accused Trump of using the allegations to divert attention from special counsel Robert Mueller's findings that Russian Federation aided Trump's 2016 campaign and that he could not exonerate the president on the question of whether he tried to impede Mueller's investigation.
Barr first confirmed publicly before Congress on April 9 that he was launching a separate investigation from the ongoing Justice Department inspector general probe into whether there was any improper or unauthorized surveillance of members of the Trump campaign prior to Trump's inauguration.
President Trump criticized FBI Director Christopher A. Wray on Tuesday, saying he gave a "ridiculous answer" during congressional testimony last week when he declined to characterize an FBI investigation of Trump campaign advisers in 2016 as "spying".
In a speech in Baltimore Monday evening, former deputy attorney general Rod Rosenstein said he believed the investigation "was justified, and closing it was not an option".
As he prepared to depart the White House on Tuesday, Trump was asked whether he retained confidence in Wray, given his answer.
That comment landed Wray in hot water with Trump, who lashed out when asked about it by reporters on Tuesday.
During an interview with CNN's John Berman, Clapper was asked if the investigation is "warranted" now that the attorney general has assigned U.S. Attorney John Durham for the job.
"It was clear there were people at the Federal Bureau of Investigation that didn't want Donald Trump to be elected president and using their position to try to stop him", Scalise said. The report also drew no conclusion on whether Trump illegally tried to impede the Mueller probe.
Durham, who was unanimously confirmed by the Senate as USA attorney in 2018, has a storied history of investigating issues of corruption and national security under both Democratic and Republican administrations.
Durham also ran a task force looking into allegedly corrupt dealings between law enforcement officials in Boston and James "Whitey" Bulger, a now-deceased crime gang leader.