Story highlights Congressional and federal investigators are probing Russia's meddling into the US elections

Former National Security Adviser Michael Flynn is seeking immunity for his testimony

(CNN) Former national security adviser Michael Flynn's offer to testify in return for immunity from prosecution hovered over the investigations Friday into Russia's communications with top aides to President Donald Trump.

Flynn's lawyer, Robert Kelner, said late Thursday that Flynn would testify in exchange for immunity. And Trump himself supported Flynn's request for immunity Friday morning in a tweet , saying, "Mike Flynn should ask for immunity in that this is a witch hunt (excuse for big election loss), by media & Dems, of historic proportion!"

Mike Flynn should ask for immunity in that this is a witch hunt (excuse for big election loss), by media & Dems, of historic proportion! — Donald J. Trump (@realDonaldTrump) March 31, 2017

But as of Friday afternoon, it did not appear that investigators had accepted his offer. A Democratic source said that Democrats on the intelligence committee are resistant to the offer.

Rep. Adam Schiff, the top Democrat on the intelligence committee, said Friday it was too early to say whether they would agree to Flynn's request, but put Flynn's offer in greater context.

"We should first acknowledge what a grave and momentous step it is for a former National Security Advisor to the President of the United States to ask for immunity from prosecution," Schiff, who later went to the White House as part of the House's investigation, said in a statement.

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