Embattled Attorney General Jeff Sessions on Tuesday blasted allegations that he or anybody in the Trump campaign colluded with the Russians as an "appalling and detestable lie" — and defended the decision to fire the FBI chief who was leading the probe of Moscow's meddling in the presidential election.

"Let me state this clearly: I have never met with or had any conversations with Russians or any foreign officials concerning any ... interference with any campaign or election," Sessions testified before the Senate Intelligence Committee.

"Further, I have no knowledge of any such conversations by anyone connected to the Trump campaign. I was your colleague in this body for 20 years, and the suggestion that I participated in any collusion or that I was aware of any collusion with the Russian government to hurt this country, which I have served with honor over 35 years, or to undermine the integrity of our democratic process, is an appalling and detestable lie."

"Please colleagues, hear me on this," Sessions continued. "I recused myself from any investigation into" Russian interference in the campaign. "I did not recuse myself from defending my honor against scurrilous and false allegations."

It was the dramatic start to Sessions' much-anticipated sworn appearance before the committee that last over two hours. And his testimony came on the heels of fired FBI Director James Comey’s turn last week in front of the same panel — a two hour and 40 minute evisceration of President Donald Trump during which Comey called the president a liar and said he was fired because of “the Russian investigation.”

Early on Tuesday, the questioning of Sessions grew heated as he declined to answer several questions about his private conversations with Trump.

Sessions stopped short of invoking executive privilege — he said only the president can do that — but explained that he was following the "longstanding" policy of the Justice Department by drawing a veil on his conversations with Trump. And he objected when Senator Ron Wyden, an Oregon Democrat, suggested he was stonewalling.

"I am not stonewalling," an emotional Sessions insisted.

But Wyden kept pressing Sessions, reminding him that Comey testified last week that there "were matters with respect to the recusal that were problematic and (Comey) couldn't talk about them."

"What are they?" Wyden asked.

"Why don't you tell me?" Sessions snapped, clearly angry. "There are none, Senator Wyden. There are none. I can tell you that for absolute certainty. This is secret innuendo leaked out there about me, and I don't appreciate it."

Then, when Wyden asked Sessions why he didn't keep out of the decision to fire Comey when he had already recused himself from participating in certain matters, the AG answered, "It did not violate my recusal."

"That answer, in my view, does not pass the smell test," Wyden shot back.

Sessions also refused to answer when Senator Angus King, an independent from Maine, asked him whether "the question of the Russian investigation" ever came up in his conversations with Trump about removing Comey.

"I cannot answer that," Sessions replied.

And when Senator Joe Manchin, a West Virginia Democrat who sometimes sides with Trump, asked Sessions whether he would feel freer to answer their questions in closed session, the AG replied: "I am not sure."

Sessions arrived at the Capitol with Washington roiling over reports that Trump was considering removing Robert Mueller, the special counsel leading the Russian probe.

It was the first time Sessions testified before Congress since he took office in February. And while Sessions — under pressure from Democrats — agreed to do so in public, no time was set aside for a closed hearing where the AG would be free to discuss classified matters.

Asked whether Trump has confidence in Mueller, Sessions answered, "I have confidence in Mr. Mueller, but I'm not going to discuss any hypotheticals."

Related: Who Is Attorney General Jeff Sessions?

Sessions was also questioned about his contacts with Russian Ambassador Sergey Kislyak — including an alleged third private meeting with the diplomat at the Mayflower Hotel in April 2016. NBC News has reported that the FBI is also looking into the alleged Mayflower meeting.

The AG forcefully denied meeting with Kislyak at the hotel. "I came there not knowing he would be there," he said.

The AG also faced other key questions like whether he still stands by his original explanation that Comey was fired for his handling of the Hillary Clinton email investigation during the campaign — and that the Russian investigation did not figure into his recommendation to remove Comey.

"That is correct," Sessions answer.

Trump, however, told NBC Nightly News anchor Lester Holt that Comey’s ouster was related to the Russia probe.

When Comey was testifying, the White House spun his admission that Trump was not personally under investigation into a “Comey vindicates Trump” talking point. And as Sessions testified a Republican rapid-response messaging team sprang into action to give the GOP take on his testimony.

At the White House, a senior administration official said they were "pretty impressed" with Sessions' testimony and they liked that he came out swinging.

But Trump was not happy when Sessions announced in March that he was recusing himself from the federal probe of Russian meddling in the presidential election.

Insisting again that he had no improper contacts with the Russians, Sessions said at the time that he was stepping aside from the mater because of his involvement in the Trump campaign. “I should not be involved in investigating a campaign I had a role in,” he said.

But Sessions’ decision to recuse himself came after he first caught flak for not disclosing during his confirmation hearing that he met with Kislyak twice during the campaign.

Sessions told NBC News a similar story on the morning in March. “I have not met any Russians at any time to discuss any political campaign,” he said. “And those remarks are unbelievable to me and are false.”

A couple hours later, Sessions was singing a somewhat different tune.

“In retrospect, I should have slowed down and said, ‘But I did meet with one Russian official a couple times, that would be the ambassador,” he told reporters.