WATCH LIVE: Attorney General Jeff Sessions faces a grilling in the Senate over Russia and Comey

U.S. Attorney General Jeff Sessions will face questions on Tuesday about his dealings with Russian officials and whether he intentionally misled Congress as a Senate panel investigates alleged Russian meddling in the 2016 U.S. presidential election.

The hearing begins at 2:30 p.m. (ET). Watch live video below:

Even before Sessions spoke, attention in Washington swiveled to whether President Donald Trump might seek to fire Robert Mueller, an ex-FBI director named last month by the Justice Department to head a federal probe into the Russia issue.

Such a move would be complicated and potentially politically explosive. The person who would be responsible for dismissing Mueller, Deputy Attorney General Rod Rosenstein, said he would not fire him without good cause and he had seen no such cause.

Sessions' testimony before the Senate Intelligence Committee, one of several congressional panels also investigating the Russia matter, was scheduled to start at 2:30 p.m. (1830 GMT), the latest chapter in a saga that has clouded the Republican president's domestic agenda.

Sessions, a former Republican U.S. senator and an early supporter of Trump's presidential campaign, will likely have to explain why he told lawmakers in January that he had no dealings with Russian officials last year.

His staffers have since acknowledged that he met twice with Russian Ambassador Sergei Kislyak. They say he did not mislead Congress because the encounters were part of his job as a senator, not as a Trump campaign surrogate. But the revelations forced Sessions to recuse himself from the Russia investigation in March.

Sessions is likely to be asked whether he played a role in Trump's decision to fire FBI Director James Comey last month. The abrupt dismissal prompted Trump's critics to charge that the president was trying to interfere with a criminal investigation.

The attorney general will also face questions about whether he met Kislyak on a third occasion. Several media outlets have reported that Comey told the Intelligence Committee in closed session last week that the FBI was examining whether Sessions met with Kislyak at a Washington hotel last year. The Justice Department has denied such a meeting occurred.

Trump has been publicly dismissive of the Russia investigation for months. A Trump confidant, Chris Ruddy, told "PBS NewsHour" on Monday the president was weighing whether to fire Mueller.

Amid the firestorm over Comey's dismissal, the Justice Department appointed Mueller last month as special counsel to oversee the probe into Russian election interference and any collusion by Trump aides. Russia has denied interfering in the U.S. election. The White House has denied any collusion.

'CATASTROPHIC' TO LET MUELLER GO

If Trump were targeting Mueller, dismissing him would not be a simple matter. Trump could recommend to the Justice Department that the special counsel be fired. Since Sessions is recused from these matters, he would likely would send such a recommendation to Deputy Attorney General Rosenstein.

In a congressional hearing on Tuesday, Rosenstein offered assurances about Mueller. "I am confident that he will have sufficient independence," he told a Senate panel evaluating a Justice Department budget request.

Rosenstein told the panel he had seen no evidence of good cause for letting Mueller go, and that lacking such evidence he would not follow any theoretical order to fire him.

Democratic Senator Dianne Feinstein said in the hearing she was disturbed by the reports on the possible firing of Mueller, saying that to dismiss him "would be catastrophic. And I do believe it would destroy any shred of trust in the president's judgment that remains over here."

"Is it fair to put that to rest?" she asked.

"As far as I'm concerned, yes," Rosenstein replied. "I appointed him. I stand by that decision ... I am going to protect the integrity of that investigation."

Newt Gingrich, a former Republican House of Representatives Speaker and Trump ally, complained this week that Mueller had hired too many Democrats. Gingrich told CBS "This Morning" that Trump called him on Monday night to discuss Mueller, but he did not think the president was considering firing him.

House Speaker Paul Ryan, a Republican, told reporters on Tuesday he had heard only rumors about Mueller, but said, "The best advice would be to let Robert Mueller do his job.”

(Additional reporting by Patricia Zengerle, Andy Sullivan, Amanda Becker, Warren Strobel and Steve Holland)