Former CIA Director John Brennan testified before a House committee Tuesday that Russia "brazenly interfered" in the U.S. presidential election and had been in contact with members of President Donald Trump's campaign team.

"I encountered and am aware of information and intelligence that revealed contacts and interactions between Russian officials and U.S. persons involved in the Trump campaign that I was concerned about because of known Russian efforts to suborn such individuals," Brennan told the House intelligence committee. "It raised questions in my mind about whether Russia was able to gain the cooperation of those individuals."

Brennan, who led the CIA from 2013 until Trump's inauguration, stopped short of saying whether he'd seen evidence of collusion – but also did not rule it out.

"I don't know whether such collusion existed," Brennan said.

The testimony marks the first time Brennan has publicly stated that he was concerned about Russia's meddling in the 2016 election.

He said he became aware of Russia's activities last summer. The revelations represent the latest confirmation from a senior law enforcement or intelligence official that Russia had interfered in the race and been in contact with Trump associates.

Brennan testified a day after The Washington Post reported that Trump had pressured his own intelligence chiefs to push back against the FBI's ongoing Russia investigation.