WASHINGTON — Former CIA director John Brennan said Tuesday that he personally warned the head of Russia’s intelligence service last year that Moscow’s interference in the U.S. election would backfire and cause severe damage to the country’s relationship with the United States.

Describing a previously undisclosed high-level discussion between Washington and Moscow, Brennan said in a phone conversation with the head of Russia’s domestic security service, the FSB, that “American voters would be outraged by any Russian attempt to interfere in the election.”

In congressional testimony, Brennan said that such meddling “would destroy any near-term prospect of improvement” in relations between the United States and Russia. Brennan said that the FSB chief, Alexander Bortnikov, twice denied that Russia was waging such a campaign, but said he would carry Brennan’s message to Russian President Vladi­mir Putin.


“I believe I was the first U.S. official to brace Russia on this matter,” Brennan said. His remarks came at the start of his testimony before the House Intelligence Committee as part of that panel’s ongoing investigation of a Russian influence campaign in the 2016 presidential election, as well as whether there was collusion or coordination between Moscow and members of the Trump campaign.

Brennan led the CIA during a critical period last year when U.S. intelligence agencies concluded that Russia was not only attempting to disrupt the election but was actively seeking to defeat Democratic candidate Hillary Clinton and help elect Trump.

Brennan was among the top officials who briefed then-President-elect Trump on that conclusion — which represented the consensus view of the CIA, the FBI and the office of the Director of National Intelligence.

Brennan became so alarmed by the Russian intervention last fall that he held classified meetings with top congressional officials to impress upon them the unprecedented nature of Moscow’s interference.

Brennan also said he thinks Russia cooperates with WikiLeaks through intermediaries.

The website released material hacked from email accounts of the Democratic National Committee and Hillary Clinton campaign officials during last year’s presidential campaign.

Brennan said that if WikiLeaks’ releases are tracked over time, it’s clear that they are often timed to coincide with certain events or to undermine national security.

He said that Russian and WikiLeaks protests that they are not working with each other are “disingenuous.”

The former CIA chief is the latest in a series of senior Obama administration officials to appear publicly before Congress in hearings that have often produced damaging headlines for Trump.

Earlier this month, former acting attorney general Sally Yates testified that she expected White House officials to “take action” after warning that then-national security adviser Michael T. Flynn had misled administration officials about his contacts with Russia.

At that same hearing, former director of national intelligence James R. Clapper Jr. said that Moscow’s leaders “must be congratulating themselves for having exceeded their wildest expectations with a minimal expenditure of resource,” a reference not only to the outcome of the 2016 race, but the chaos that has characterized the early months of the Trump administration.

Brennan has feuded publicly with Trump over the president’s treatment of intelligence agencies. In January, he lashed out at Trump for comparing U.S. spy agencies to Nazi secret police.

Brennan was particularly offended by Trump’s remarks during a speech at CIA headquarters on the day he was inaugurated. Trump used the CIA’s Wall of Honor — a collection of engraved stars marking lives of agency operatives killed in the line of duty — to launch a rambling speech in which he bragged about his election victory.

Brennan called the appearance “despicable” and said that Trump should be “ashamed.”