Former FBI Director James Comey's highly-anticipated testimony on Capitol Hill did not lack for riveting moments. Here are some of the highlights:

Comey accused the Trump administration of spreading "lies, plain and simple" about him

The ex-FBI chief, who was abruptly fired by President Donald Trump last month, testified under oath that he was "confused" and "concerned" when the president claimed he had been axed for undermining morale at the FBI.

"Those were lies, plain and simple," Comey said.

Comey said he was "honestly concerned" Trump might "lie" about their interactions

Comey said he documented his private conversations with Trump, in part because of the "nature of the person."

"I was honestly concerned that he might lie about the nature of our meetings," Comey said of the president.

Comey said he is "sure" the special counsel will look into whether Trump obstructed justice

Comey said he believed Trump directed him to stop investigating former national security adviser Michael Flynn, who was fired for misleading the White House about his contacts with Russia.

Comey told the Senate Intelligence Committee that Trump told aides, such as Attorney General Jeff Sessions and his son-in-law Jared Kushner, to leave the Oval Office on Feb. 14. Comey said Trump then brought up ending the probe into Flynn.

At his hearing, Comey said it was not for him to say whether the president sought to obstruct justice.

But he added he was "sure" the special counsel, Robert Mueller, will look into that.

Comey wants Trump to release recordings — if they exist

Trump has suggested he secretly recorded his one-on-one conversations with the former FBI head.

"Lordy, I hope there are tapes," Comey said.

Comey said he believes he was fired over the Russia investigation

Comey testified that he did not know for sure why he was axed. But he said: "I take the president at his word that it was because of the Russia investigation," Comey said, referring to news reports about Trump's decision.

"I know I was fired because of something about the way I was conducting the Russia investigation was in some way putting pressure on him, in some way irritating him, and he decided to fire me because of that," Comey later said.

Comey said he leaked his memos in hopes that might lead to a special counsel

Comey testified that he decided to orchestrate a leak of memos he wrote after encounters with Trump.

"I asked a friend of mine to share the content of a memo with the reporter," Comey said. "I didn't do it myself for a variety of reasons, but I asked him to because I thought that might prompt the appointment of a special counsel."

That friend is Columbia Law Professor Daniel Richman, friends of the professor confirmed to NBC News.

Comey said there were facts that would make Jeff Sessions' involvement in the Russia investigation "problematic"

Comey said the FBI expected Attorney General Jeff Sessions to recuse himself from the Russia probe, but he could not elaborate.

"We were also aware of facts I can't discuss in an open setting that would make his continued involvement in a Russian investigation problematic," Comey told lawmakers.

! Comey says there was facts that would make Sessions involvement in the Russia investigation “problematic” but he can’t discuss in public pic.twitter.com/H1rNT4SBN1 — Bradd Jaffy (@BraddJaffy) June 8, 2017

Comey wanted to be clear: Russia interfered in the 2016 presidential election

"There's no fuzz on that," Comey said.

Comey declined to say whether he believes the Trump campaign colluded with Russia during the election

Arkansas Sen. Tom Cotton asked Comey: "Do you believe Donald Trump colluded with Russia?"

Comey responded: "It's a question I don't think I should answer in an open setting."

He added: "I'm not trying to suggest by my answer something nefarious."