The House Intelligence Committee’s top Democrat says a request by the fired US national security adviser for immunity to testify to the panel is “momentous”.
Representative Adam Schiff said they were interested in hearing Michael Flynn’s evidence, but it was too early to shield him from any prosecution.
Two congressional committees and the FBI are investigating alleged Russian meddling in the US election.
Mr Flynn’s ties with Russia have been under scrutiny.
The retired army lieutenant general was sacked in February after misleading the White House about a conversation he had with the Moscow ambassador shortly after the election.
On Thursday night, his lawyer said in a statement that his client “has a story to tell” to the Capitol Hill inquisitors.
But the attorney added it would not be reasonable to submit to questioning in a “witch-hunt environment” without assurances against “unfair prosecution”.
Why immunity? Anthony Zurcher, BBC News, Washington
Michael Flynn may have a “story to tell”, but what it is at this point is anybody’s guess.
Donald Trump’s critics will probably imagine grand revelations of possible campaign contacts with Russian operatives or even the “c” word – collusion. Beyond the news reports of ongoing conversations between Flynn’s lawyer and federal investigators, however, there is no firm ground for such speculation.
It’s entirely possible the immunity request is nothing more than the former senior Trump adviser attempting to insulate himself from legal trouble if he were to answer detailed questions about his foreign contacts and lobbying efforts. For instance, if he actively represented overseas interests, he may have run afoul of federal disclosure rules.
There’s also the chance that Flynn could be uneasy about what he told FBI agents in January, when they asked about his conversations with Russian Ambassador Sergei Kislyak. Go to BBC to read more.