WASHINGTON — US Attorney General Jeff Sessions on Tuesday vehemently denied any collusion with Russia to tilt last year’s election in Donald Trump’s favour, branding the suggestion an "appalling and detestable lie."

In closely-watched congressional testimony, Sessions angrily denounced allegations he acted improperly during a series of meetings with Russian officials -- or that he knew of any attempt at collusion by members of the Trump campaign team.

And he repeatedly refused to reveal whether he had spoken to the president regarding James Comey’s handling of the probe into Russian election meddling -- which the former FBI director believes to be the reason he was fired.

A Trump loyalist and early backer of the billionaire businessman’s presidential bid, the 70-year-old Sessions has recused himself from all ongoing Russia investigations.

But the nation’s top law enforcement official -- who recommended Comey’s dismissal last month -- has himself become a focal point in the crisis roiling the White House.

Sessions kicked off his testimony before the Senate Intelligence Committee by asserting that he had "never met with or had any conversations with any Russians" about interference in the 2016 presidential race.

"I have no knowledge of any such conversations by anyone connected to the Trump campaign," he said. "The suggestion that I participated with any collusion, that I was aware of any collusion with the Russian government to hurt this country... is an appalling and detestable lie."

The appearance was Sessions’s first sworn public testimony since being confirmed as attorney general in February, and comes as political intrigue pulses through the US capital following Comey’s explosive testimony last week.

During the two-and-a-half hour hearing, he engaged in testy exchanges with several senators who pressed him for details on his discussions with Trump -- which he refused to provide in the name of confidentiality.

Some Democrats grew impatient, warning Sessions was stonewalling on vital issues.

"You are obstructing that congressional investigation by not answering that question," charged Senator Martin Heinrich. "Your silence... speaks volumes."

Sessions responded: "I am not stonewalling. I am following the historic policies of the Department of Justice."

’Innuendo’

Testifying last week before the same committee, Comey recalled that Trump had asked him to "let go" of a probe into onetime national security advisor Michael Flynn -- exposing the president to accusations of obstruction of justice, a potentially impeachable offense.

Flynn was sacked two weeks into the job amid concerns he lied over his Russian contacts, becoming the first high-profile victim of the scandal that has overshadowed Trump’s young presidency.

Trump has recently expressed frustration with Sessions, who has come under pressure over his own Russia contacts.

While the Justice Department has said Sessions recused himself in March because of his involvement in Trump’s campaign, Comey testified that the FBI knew of information that would have made it "problematic" for Sessions to be involved.

But the attorney general’s pushed back hard when asked what those problematic matters could be, retorting: "There are none. I can tell you that for absolute certainty.

"This is a secret innuendo being leaked out there about me, and I don’t appreciate it," he added.

’No knowledge’ of Russia probe

Barely a month after Trump dismissed Comey, rumors have been circulating that he may yet seek to sack Robert Mueller, the special counsel appointed following the FBI chief’s ouster to head the agency’s Russia investigation. Sessions declined to comment on those reports, stating only that he had "confidence" in Mueller and would not be involved in any effort, should it arise, to fire the special counsel.

He also said that since his recusal, "I have no knowledge about this investigation" beyond media reports.

Addressing allegations that he had unreported meetings with Russian officials while he advised the Trump campaign, Sessions said he had already acknowledged two encounters last year with Ambassador Sergey Kislyak.

But he denied any substantive discussion with Kislyak at a third encounter, at an April 27, 2016 reception for Trump at Washington’s Mayflower Hotel. Sessions also pushed back against Comey’s suggestion he may have failed to take appropriate steps to protect the FBI chief from political pressure.

At the conclusion of a February 14 meeting, the sacked FBI chief testified, Trump urged everyone but Comey to leave the Oval Office, including Sessions.

Comey said the president then leaned on him to halt the Flynn investigation.

Sessions said he learned from Comey that he felt concerned about being left alone with the president but that, since Comey did not relay details of the conversation, he had no way of knowing it was improper.

Tuesday’s hearing was followed by predictably partisan reaction from Republicans and rival Democrats.

"With no evidence of collusion, wrongdoing, or obstruction of justice by President Trump or the White House, how much longer is this going to go on," said Republican National Committee Chair Ronna McDaniel, praising Sessions’s "honesty and professionalism".

However Democrat Congressman Jim Langevin said Sessions fell short of the standard of evidence required at such a hearing.

"The Attorney General’s testimony this afternoon was unsubstantial, unresponsive, and unacceptable. Mr Sessions -- like every government employee -- has an obligation to answer to the oversight of Congress. He failed that obligation and his oath to the Constitution with his stonewalling of senators." — AFP