“It raised questions in my mind about whether Russia was able to gain the cooperation of those individuals,” he said, adding that he did not know whether the Russian efforts were successful.
He added, “I don’t know whether such collusion existed.”
It was the first time he publicly acknowledged that he was concerned about possible ties between Russia and the Trump campaign.
He said he left office in January with many unanswered questions about the Russian influence operation. Intelligence officials have said Russia tried to tip the election toward Mr. Trump.
Mr. Brennan last summer about signs of Russian election meddling that he held urgent, classified briefings for eight senior members of Congress, speaking with some of them over secure phone lines while they were on recess. In those conversations, he told lawmakers there was evidence that Russia was working to elect Mr. Trump president.
Mr. Brennan was also one of a handful of officials who briefed both President Barack Obama and Mr. Trump in January on a broad intelligence community report that President Vladimir V. Putin of Russia had personally ordered an “influence campaign” targeting the presidential election.
— Matt Apuzzo
Watch the hearing here:
Trump asked two intelligence chiefs to push back on the inquiry, officials say.
Mr. Trump asked two of the country’s top intelligence officials to make public statements saying there was no evidence of collusion between his campaign and Russian officials, hoping to undercut an F.B.I. investigation into meddling by Russia in the 2016 presidential election, two former American officials said.
The requests were made in late March to Dan Coats, the director of national intelligence, and Adm. Michael S. Rogers, the chief of the National Security Agency. Both men rebuffed the request, which they saw as an inappropriate effort to inject politics into an intelligence and law enforcement matter, the former officials said.
Days before, James B. Comey, then the F.B.I. director, had publicly acknowledged for the first time that the bureau was running a broad counterintelligence investigation into Russia’s interference in the presidential campaign and any possible collusion between associates of Mr. Trump and Russian officials. The revelation stung Mr. Trump, who has repeatedly said there was no collusion, and he wanted Mr. Coats and Admiral Rogers to publicly back him.
On the day of Mr. Comey’s hearing, a call from the White House switchboard came in to Mr. Coats’s office with a request to speak to the director, a former intelligence official said. Calls from the switchboard are usually from the highest officials at the White House — the president, the vice president or the national security adviser.
Mr. Coats took the call. The official would not confirm what was discussed.
Mr. Trump’s requests to Mr. Coats and Admiral Rogers were .
— Mark Mazzetti and Matthew Rosenberg
Coats declines to detail conversations with Trump.
Senator John McCain of Arizona, the Republican chairman of the Armed Services Committee, opened questioning at a hearing Tuesday by asking about Mr. Trump’s request to publicly dispute that any evidence exists of collusion between the Trump campaign and Russia.
“Is that an accurate reporting, Director Coats?” Mr. McCain asked.
Mr. Coats said he could not publicly discuss the subject.
“As the president’s principal intelligence adviser, I’m fortunate to spend a significant amount of time with the president discussing national security interests and intelligence as it relates to those interests,” Mr. Coats said. “We discuss a number of topics.”
But because of the sensitivity of their conversations, Mr. Coats said, “it’s not appropriate for me to comment publicly on any of that.”
Mr. McCain asked whether reports based on unnamed sources are problematic.
“Lives are at stake in many instances, and leaks jeopardize those lives,” Mr. Coats said.
— Emmarie Huetteman
More Flynn documents are being subpoenaed.
The Senate Intelligence Committee issued subpoenas Tuesday for documents from two businesses owned by Michael T. Flynn, Mr. Trump’s former national security adviser, the committee’s senior members said.
The move, coming the day after , escalates his standoff with Senate investigators looking into potential collusion between Mr. Trump’s associates and Russian officials.
Senator Richard M. Burr of North Carolina, the committee’s Republican chairman, said panel members had also written back to Mr. Flynn’s legal team, requesting clarity about whether the Fifth Amendment could indeed shield an individual from producing documents, as well as challenging his claim that the committee’s previous requests for documents lacked specificity.
Mr. Burr left open the possibility of holding Mr. Flynn in contempt of Congress.
“At the end of that option is a contempt charge,” he told reporters. “And I’ve said that everything is on the table.”
But the committee members are not ready to take that step, Mr. Burr said, adding that they want to give Mr. Flynn the opportunity he requested to tell his story.
Senator Mark Warner of Virginia, the panel’s top Democrat, said the subpoenas were for the firms Flynn Intel LLC and Flynn Intel Incorporated.
“We disagree with General Flynn’s lawyers’ interpretation of taking the Fifth,” he said. “It is even more clear that a business does not have a right to take the Fifth as a corporation.”
Flynn Intel Group was hired by a Turkish-American businessman to represent Turkish interests in a dispute with the United States government last year, while Mr. Flynn was advising the Trump campaign. He was paid more than $500,000. Mr. Flynn, who initially did not file the paperwork to disclose this connection, belatedly registered with the government as a foreign agent after being forced out of the Trump administration.
— Emmarie Huetteman
Official says Russia may have had two aims.
One of the enduring questions about Russia’s interference in the 2016 presidential election is whether the Russian government wanted to simply hurt Hillary Clinton or was actively trying to secure the election of Mr. Trump.
Asked which one he believed to be the case, Mr. Brennan said: “My assessment is it was both.”
Mr. Putin had long viewed Ms. Clinton as an implacable foe, he explained, and saw in Mr. Trump a businessman who might take a softer line on Russia.
“They felt that Mr. Trump, being a bit of an outsider, that they in the past had some good relations with businessmen who happened to elevate into positions of government authority,” Mr. Brennan said.
“They clearly had a more favorable view toward Mr. Trump and actions they were taking were trying to increase his prospects, even though they probably thought they were not that great,” he said.
“They anticipated that Secretary Clinton was going to win the election, and I believe they tried to damage and bloody her before the election,” Mr. Brennan said.
Asked whether the Russians collected intelligence on Mrs. Clinton that they did not use during the campaign, Mr. Brennan responded that if they did, “their efforts to denigrate her and hurt her would have continued during her presidency.”
— Matthew Rosenberg
Ethics experts clear Mueller as the special counsel.
The Trump administration said Tuesday that ethics experts had decided that Robert S. Mueller III, the special counsel overseeing the federal investigation into possible Russian interference in the election, could carry out the inquiry even though his former law firm represents some of Mr. Trump’s family members and his former campaign chairman.
The firm, WilmerHale, represents Paul Manafort, the former Trump campaign chairman, and Mr. Trump’s daughter Ivanka and son-in-law, Jared Kushner. While Mr. Mueller did not personally represent them, Reuters reported that the White House was using conflict-of-interest rules to undermine the investigation.
Mr. Mueller resigned his role as a partner at WilmerHale to become the special counsel.
In a statement on Tuesday, the Justice Department noted that its regulations permit a waiver to be issued and noted that professional responsibility rules permit Mr. Mueller to participate in matters involving his former law firm’s clients “so long as he has no confidential information about the client and did not participate in the representation.”
“Department ethics experts have reviewed the matters and determined that Mr. Mueller’s participation in the matters assigned to him is appropriate,” the statement said.
— Charlie Savage
Russia may try to interfere in 2018 elections, a former C.I.A. director warns.
Asked whether he believed Russia would try to interfere in the 2018 midterm elections, Mr. Brennan said, “I have, unfortunately, a grudging respect for Russian intelligence capabilities, their aggressiveness, their pervasiveness and their determination to do what they can do undermine this country’s democracy and democratic institutions.”
He said Russia would continue to try to “exploit elections,” but was also looking at other targets.
Russian intelligence was aggressively trying to collect intelligence about prominent Americans both inside and outside the government, Mr. Brennan said. The Russians would use whatever information they obtained to gain influence over individuals who help shape American opinion.
— Matthew Rosenberg
An earlier version of a home page summary for this article misidentified the lawmakers before whom Mr. Brennan was testifying. As the article correctly notes, he was at a hearing of House members, not senators.