The chairman of the Senate Judiciary Committee on Thursday demanded the FBI disclose whether it ever briefed or warned President Trump during the 2016 presidential race about attempts by the Russian government to infiltrate his campaign.

In a letter to FBI Director Chris Wray, Sen. Chuck Grassley Charles (Chuck) Ernest GrassleyGOP set to release controversial Biden report McConnell locks down key GOP votes in Supreme Court fight Senate Republicans face tough decision on replacing Ginsburg MORE (R-Iowa) cites recent reports that the bureau was wiretapping Trump's campaign chairman Paul Manafort in the summer of 2016 over concerns about ties to Russian figures.

It also noted past reports in The Washington Post and Circa that Sen. John McCain John Sidney McCainMomentum growing among Republicans for Supreme Court vote before Election Day McConnell urges GOP senators to 'keep your powder dry' on Supreme Court vacancy McSally says current Senate should vote on Trump nominee MORE's (R-Ariz.) 2008 presidential campaign got a warning from intelligence officials about possible foreign ties to Manafort and McCain's campaign manager Rick Davis when they were associated with the senator.

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Grassley asked whether the bureau ever delivered a similar "defensive" briefing to Trump last year.

"If the FBI did provide a defensive briefing or similar warning to the [Trump] campaign, then that would raise important questions about how the Trump campaign responded," Grassley wrote.

"On the other hand, if the FBI did not alert the campaign, then that would raise serious questions about what factors contributed to its decision and why it appears to have been handled differently in a very similar circumstance involving a previous campaign."