Speaking publicly for the first time since his abrupt firing, former FBI director James Comey told a Senate panel Thursday that he took President Trump’s words as “a direction” to drop the investigation of ex-national security adviser Michael Flynn’s ties to Russia.

Comey said he now believes Trump fired him to relieve pressure from the ongoing FBI investigation into possible collusion between Trump campaign associates and Russia. The U.S. intelligence community has accused Moscow of seeking to influence the 2016 presidential election by hacking the Democratic National Committee and Hillary Clinton’s campaign.

“I was fired in some way to change the way the Russia investigation was being conducted,’’ Comey said. “That is a big deal. On top of that, the Russia investigation itself is vital because of the threat. And if any American were part of that, that is a very big deal.’’

At the center of the testimony was a Feb. 14 meeting at the White House. In that meeting, Comey said Trump strongly defended Flynn, arguing that his former national security adviser “hadn’t done anything wrong’’ in his prior contact with Russian ambassador Sergey Kislyak. Flynn had been fired the day before for lying to administration officials, including Vice President Pence, about his communications with Kislyak.

“I hope you can see your way clear to letting this go,” Comey quoted the president as saying. “He is a good guy. I hope you can let this go.”

Comey told the senators that he was “so stunned by the conversation that I just took it in.”

He also said that he hoped the president was serious when he tweeted that there might be tapes of the conversation. “Lordy, I hope there are tapes,” Comey said, later promising to consent to the release of them if they exist. “The president surely knows whether he taped me, and if he did, my feelings aren’t hurt. Release all the tapes. I’m good with it.”

Among of the most stunning and consistent themes running throughout more than two hours of testimony was that Comey believed the president could not be trusted.

The concern, rooted in Comey’s first Jan 6 meeting at Trump Tower with then-president-elect Trump, compelled the former director to compose written records of his communications with the president because he worried Trump might “lie’’ about what transpired.

After leaving that tense initial briefing, Comey said he immediately created a written record of it.

“It was the subject matter and the person I was interacting with,” he said. “It was the nature of the person. I was honestly concerned that he would lie about the nature of our meeting. I felt I’ve got to write it down and I’ve got to write it down in a detailed way. I knew there might come a day when I would need a written record to defend me and the FBI.’’