Donald Trump and his allies insist that there’s no evidence whatsoever of collusion between the Kremlin and Trump Tower. The former director of the Central Intelligence Agency isn’t so sure.

John Brennan, Barack Obama’s third CIA director, told Congress he has “unresolved questions” over whether Russia succeeded in getting Donald Trump associates to do their bidding, “wittingly or unwittingly.”

Questioned aggressively by leading panel Republican Rep. Trey Gowdy of South Carolina, Brennan repeatedly pushed back against saying if he saw “evidence” of “collusion” between Trump and Russia – a framing favored by the White House and its GOP allies, who argue no such collusion exists.

“I don’t do evidence, I do intelligence,” Brennan said, saying the FBI was the proper agency to follow up as to whether the identified ties amount to evidence – a term with legal connotation and implication – of what Gowdy called “collusion, collaboration or conspiracy.”

“I don’t know whether or not such collusion – that’s your word – existed, I do not. But I know there was a sufficient basis of information and intelligence that required further investigation by the bureau to determine whether U.S. persons were actively conspiring, colluding, with Russian officials,” Brennan said.

Brennan declined to specify who in Trump’s orbit prompted those concerns, repeatedly using the euphemism “U.S. persons” in an occasionally testy public hearing on Tuesday of the House intelligence committee’s Russia investigation.

But Brennan revealed that starting in late July, his “unresolved questions” about such “contacts and interactions” with Russian officials that led him to pass highly classified intelligence to the FBI for what would become the ongoing FBI investigation of Trump’s associates, now helmed by former director Robert Mueller.

While Brennan left open the prospect those ties “might have been benign,” they came in the context of Russia’s summer 2016 push to interfere in the presidential election, Brennan said, and so “seeing these types of contacts and interactions in the same amount of time raised my concern.”

The former CIA director also revealed that he personally called the head of Russia’s domestic intelligence agency, FSB director Alexander Bortnikov, on August 4, 2016 to “warn” him that Russian interference in the election would “destroy any near-term prospect for improvement in relations” with Washington. Brennan said his call, which came with White House consent, was the first official interaction with the Russians on the election hacking.

Bortnikov denied “Russia was doing anything to influence our presidential election and that Moscow is a traditional target of blame by Washington for such activities,” which Brennan said was an “expected” reaction by the FSB chief.

‘Specter of Possible Obstruction Grows Larger’

Brennan’s Capitol Hill appearance marked an opportunity for the beleaguered, divided committee to reset after a calamitous two months.

Though the House intelligence committee is one of the principal fora for investigating ties between the Trump campaign and Russia, the only prior public hearing it has held, on March 20, fractured between Democrats asking witnesses about Russia and Republicans asking them about intelligence leaks. Since then, the panel’s chairman, Devin Nunes, a member of Trump’s national-security transition team, had to back off leading the inquiry after he was exposed as running interference for the White House. Although Nunes couched his departure as a “temporary” measure, he did not attend Tuesday’s testimony, either the public or the closed-door session.

The committee’s divisions come as the stakes for its inquiry have grown substantially. Trump has since fired the star witness of its March hearing, FBI director Jim Comey, and justified it to NBC’s Lester Holt as a maneuver to shut down the bureau’s probe into Team Trump’s Russia connections. It subsequently emerged that Trump, in an Oval Office meeting with Russian Foreign Minister Sergey Lavrov and Ambassador Sergey Kislyak, shared intelligence from Israel about a highly sensitive operation against Islamic State, something Trump blurted out confirmation of doing in a Monday meeting with Benjamin Netanyahu. And then on Monday night, the Washington Post reported that Trump asked director of national intelligence Dan Coats and NSA director Mike Rogers to quash the Russia probe, prompting the panel’s top Democrat, Adam Schiff, to say the “specter of possible obstruction has grown larger and more troubling.”

‘I Certainly Would Not Follow Such a Directive’

Brennan often declined to wade into many of the politically-charged allegations against Trump that emerged after Brennan left the CIA on January 20, particularly those concerning obstruction of justice. But he intimated that it would be inappropriate for Trump to ask Comey, Rogers or Coats to stifle the inquiry.

“I have never been asked that, and if I was, I certainly would not follow such a directive,” Brennan said.

Coats made his own appearance on Tuesday before the Senate. He refused to confirm or deny the Post ’s reporting, saying “on this topic, as well as other topics, I don’t feel it’s appropriate to characterize discussions and conversations with the president,” but signaling that he believed the FBI and congressional inquiries are “in place to get us to the right conclusion so that we can move on with a knowing result.”

Coats further testified that he had yet to discuss with Trump the president’s meeting with Lavrov and Kislyak, something Brennan indicated he found disturbing from the perspective of safeguarding intelligence secrets.

Though Brennan said he himself had shared counterterrorism intelligence with the Russians, he said he did so in compliance with well-established protocols: sharing intelligence through established intelligence channels, “not with visiting foreign ministers or local ambassadors”; and if the information came from one of the CIA’s foreign partners, sharing it only with that partner’s foreknowledge and consent.

“I don’t know what was said or shared,” during Lavrov and Kislyak’s Oval Office visit, “but if the reports in the press are true that Mr. Trump decided to spontaneously share some intelligence with the Russians, I think he would have basically violated two protocols,” Brennan said.

In claiming that Trump shared nothing inappropriate in his meeting with Kislyak and Lavrov, the president and his national security adviser, H.R. McMaster, have insisted that he discussed no “sources or methods” with the Russians. But Brennan said that the reason protocol mandates discussing with a foreign partner before disseminating that partner’s intelligence is to ensure “even just by providing the substance of it, isn’t going to reveal sources and methods and compromise the future collection capability.”

Blame Obama

Tuesday’s hearing did not display the same naked partisanship that March’s exposed. Instead, with the exception of Gowdy, Republicans jousted more subtly with their witnesses this time.

Mike Conaway, one of the three GOPers whom Nunes placed in charge of the panel’s probe, barely spoke. The other two, Gowdy and Florida’s Tom Rooney, pressed Brennan to condemn anti-Trump leaks attributed to the intelligence agencies, which Brennan did without hesitation – Brennan, after all, was CIA director when the agency surreptitiously accessed the classified work product of Senate investigators probing CIA torture. They also intimated that such leaks jeopardized GOP support for renewal of an expiring surveillance authority that the NSA and FBI consider their top 2017 legislative priority and which the panel traditionally supports – with such support still appearing on the committee’s website.

An exception, however, came when Ohio Republican Brad Wenstrup suggested that the president whom Russia used as a tool was not Trump but Obama.

Saying he was “concerned about the process” for when the CIA would recommend the FBI investigate a potential counterintelligence compromise of a US official, Wenstrup mentioned a 2012 embarrassment for Obama – when he was caught on a hot mic telling Putin ally Dmitry Medvedev he would have “more flexibility” to discuss missile defense with Putin after his reelection.

“That was a direct conversation between the heads of government and state, between two countries. I’m not going to respond… I try to avoid getting involved in political issues, partisan issues,” Brennan told Wenstrup.