Updated at 12:41 p.m. ET

Former CIA Director John Brennan told the House Intelligence Committee Tuesday that Russia "brazenly interfered in the 2016 election process," despite U.S. efforts to warn them off. Brennan testified in an open session of the committee, one of a handful of congressional committee now investigating Russian meddling in the 2016 election.

Brennan said he told his Russian counterpart, the head of Russia's FSB, last August that if Russia pursued its efforts to interfere, "it would destroy any near-term prospect for improvement in relations" between the two countries. He said Russia denied any attempts to interfere.

In his opening statement, Brennan also recounted how he had briefed congressional leaders in August of last year, including House Speaker Paul Ryan, R-Wisc., Senate Majority Leader Mitch McConnell, R-Ky., and the chairs and ranking members of the House and Senate Intelligence Committees about the "full details" of what he knew of Russia's interference in the 2016 election. Brennan said he became convinced last summer that Russia was trying to interfere in the campaign, saying "they were very aggressive."

Brennan said he is "aware of information and intelligence that revealed contacts and interactions between Russian officials and U.S. persons involved in the Trump campaign." Brennan said that concerned him, "because of known Russian efforts to suborn such individuals," and that it raised questions about whether or not the Russians "were able to gain the cooperation of those individuals." Brennan added he didn't know if "collusion existed" between the Russians and those he identified as involved in the Trump campaign.

While Brennan would not specifically identify any individuals associated with the Trump campaign who had contacts with Russian officials and would not opine as to whether there was any collusion or collaboration, he did tell lawmakers why he was concerned about the contacts occurring against the general background of Russian efforts to meddle in the election. Brennan said he's studied Russian intelligence activities over the years, and how they've been able to get people to betray their country. "Frequently, individuals on a treasonous path do not even realize they're on that path until it gets to be too late," he said.

Brennan said Russia was motivated to back Donald Trump in the presidential election because of a "traditional animus" between Democratic nominee Hillary Clinton and Russian President Vladimir Putin. He told committee members there had not been a good relationship between Putin and the Clintons over the years. What's more, Brennan said Putin blamed Hillary Clinton's actions as secretary of state during the Obama administration for domestic disturbances inside Russia. He said Putin was concerned Clinton would be more "rigid" on issues such as human rights if elected president.

But Brennan told the committee he believed that Russia anticipated that Clinton would be the likely winner of the presidential race, and that they tried to "damage and bloody" her before Election Day. Had she won, Brennan said, Russia would have continued to attempt to "denigrate her and hurt her" during her presidency. If Russia had collected more information about Clinton that they did not use against her during the campaign, Brennan said they were likely "husbanding it for another day."

On another question, Brennan criticized President Trump's reported sharing of classified intelligence with Russia officials. Brennan said if reports were accurate, Trump violated "protocols" by sharing the information with Russia's foreign minister and ambassador to the U.S.

Brennan also said he was "very concerned" by the release of what he said appears to be classified information from the Trump administration. He said there appear to be "very, very damaging leaks, and I find them appalling and they need to be tracked down."

Brennan led the CIA during the Obama administration from 2013-2017. Prior to that, Brennan was a top counterterrorism and homeland security adviser to President Barack Obama.

Tuesday's public hearing represented an effort by the House Intelligence Committee to get its Russia investigation back on track after political squabbling and concerns about information-sharing between its chairman, Rep. Devin Nunes, R-Calif., and White House aides sidelined the committee's work. After pressure from Democrats, Nunes has turned over leading the committee's Russia investigation to Rep. Mike Conaway, R-Texas, who is also a CPA.

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