US Attorney General Jeff Sessions has branded any accusation he took part in collusion with Russia during the 2016 presidential election as an “appalling and detestable lie”.

Senator Sessions, addressing the Senate Intelligence Committee on Wednesday morning (AEST), denied claims he met Russian ambassador Sergey Kislyak at Washington’s Mayflower Hotel during the Mr Trump’s election campaign.

His assertion comes despite reports that the FBI was investigating whether the contact took place as part of its probe into alleged interference by Moscow in the US election.

“I did not have any private meetings nor recall any private conversations with any Russian official at the Mayflower hotel,” Senator Sessions said.

The Attorney General testified that he never had any meetings with officials from Russia or anywhere else about interference in the US elections.

“Further, I have no knowledge of any such conversations by anyone connected to the Trump campaign,” he said.

“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 honour for 35 years, or to undermine the integrity of our democratic process, is an appalling and detestable lie.”

The Attorney General’s appearance before the Senate comes a week after explosive testimony from former FBI director James Comey, in which accused President Trump of lying to the US public.

Senator Sessions confirmed that he had left Mr Comey on his own with Mr Trump in the Oval Office February 14, but declined to say whether he was ordered to do so by the President citing the need to keep his conversations with him private.

He also said that Mr Comey later told him he was concerned about the meeting, but he did not say that something improper occurred.

Mr Comey was fired by the President, on Senator Sessions’ recommendation, during the FBI’s Russia investigation.

A subsequent memo leaked by Mr Comey prompted claims that President Trump attempted to influence the top law enforcement official into dropping its probe into former national security adviser Michael Flynn.

The Attorney General’s appearance before the Senate Committee comes after he recused himself from the Russia investigation.

Senator Sessions said, his recusal from the Russia investigation did not mean that he should not fulfill his oversight duties over the FBI, amid claims from the Democrats that he should have not played a role in Mr Comey’s firing.

“I recused myself from any investigation into the campaigns for president, but I did not recuse myself from defending my honour against scurrilous and false allegations,” he said.

“At all times throughout the course of the campaign, the confirmation process, and since becoming Attorney General, I have dedicated myself to the highest standards.”

Senator Sessions said he and Deputy Attorney General Rod Rosenstein had a “clear view … that we had problems [with Mr Comey] and it was my best judgement that a fresh start at the FBI was the appropriate thing to do. And when asked I said that to the President”.

He said despite his concerns over problems at the FBI, he never raised that with Mr Comey.

When asked about  President Trump’s contention that he fired Mr Comey with the Russia probe in mind, and regardless of any recommendation from anyone else, Senator Sessions said: “I guess I’ll just have to let his words speak for themselves. I’m not sure what was in his mind specifically.”

Sessions refused to say whether he had ever discussed the Russia investigation with President Trump, saying he could not disclose private communications with the President.

He also said he did not know whether the President records his conversations in the White House.

Senator Sessions passionately defended President Trump.

“The people of this country expect an honest and transparent government, and that is what we are giving them,” he said.

“This President wants to focus on the people of this country to ensure they are treated fairly and kept safe,” the Attorney General said.

President Trump watched Senator Sessions’ testimony while aboard Air Force One, a White House aide told CNN.