Trump's ex-National Security Advisor Gen Mike Flynn has agreed to testify to Congress if promised immunity from prosecution, according to the Wall Street Journal.
Flynn was briefly Trump's NSA before he was forced to resign when it emerged that he had lied regarding his contacts with Russia.
This is a surprising move given the Russia story has so far been a lot of smoke without any real fire visible.
Congress is investigating whether Russia interfered with the US elections in 2016.
Congress is yet to agree to Flynn's demands.