US 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 the Kremlin's alleged involvement in the 2016 presidential election.
Sessions' testimony before the Senate Intelligence Committee, scheduled to start at 1830 GMT, has the potential for high drama as the Russia probe continues to dominate US politics, side-lining President Donald Trump's domestic agenda.
The former Republican US senator from Alabama, one of Trump's most avid supporters on the campaign trail, will likely have to explain why he told lawmakers in January he had no dealings with Kremlin 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 surrogate of the Trump campaign.
But the revelations forced Sessions to rescue himself from the Russia investigation in March, and it is now being handled by a special counsel.
Sessions will likely be asked whether he played a role in Trump's surprise decision to fire FBI Director James Comey last month, a move that caused Trump's critics to charge that he was trying to interfere with a criminal investigation.
The attorney general could also face questions about whether he met Kislyak on a third occasion. Several media outlets have reported that Comey told the Intelligence Committee last week that the FBI was examining whether Sessions met with Kislyak at a Washington hotel last year.
It is not clear whether Sessions plans to answer all the questions or if he will invoke executive privilege to avoid disclosing private conversations with the president.
Some members of the Intelligence Committee, frustrated by the tight-lipped performance of other administration officials last week, said they were not going to allow Sessions to follow suit.
"That's just not going to be acceptable tomorrow," said Senator Ron Wyden, a Democrat on the committee.
One of those administration officials, Admiral Michael Rogers, head of the National Security Agency, met with members of the Intelligence Committee in a closed-door session, according to the agency.
A Trump confidant, Chris Ruddy, told "PBS NewsHour" on Monday that the president was weighing whether to fire the special counsel now heading up the investigation, former FBI Director Robert Mueller. One of Trump's lawyers, Jay Sekulow, declined to rule out that possibility on Sunday.
Russia has denied interfering in the US election. The White House has denied any collusion with Moscow.