Washington (CNN) FBI Director Christopher Wray, responding to a question Friday about special counsel Robert Mueller's investigation into Russian interference in the 2016 election, said he believes the US rival "poses a very significant counterintelligence threat."

Asked at the Council on Foreign Relations about Mueller's characterization of Russian interference in 2016 as "sweeping and systematic," Wray said that although "everybody has their own adjectives," he agreed the threat is serious.

Reiterating what officials have said in the past , Wray said, "we did not see in 2018 was any material effect on election infrastructure." And while Wray said "enormous strides" have been made since 2016, the FBI director warned adversaries are going to "keep at it" and the intelligence community very much viewed the 2018 midterm elections as the "dress rehearsal" for 2020.

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The remarks by Wray, who was appointed by President Donald Trump, are in stark contrast to reactions to Russian meddling by top members of the Trump administration, including the President himself.

On Tuesday, White House senior adviser Jared Kushner downplayed Russian interference , suggesting that the Mueller investigation was more harmful to the US.