The Senate Intelligence Committee issued a subpoena for President Trump's former national security adviser Gen. Michael Flynn.
In a joint announcement, Sen. Richard Burr, R-N.C., chairman of the Senate Select Committee on Intelligence, and Sen. Mark Warner, D-Va., vice chairman of the panel, said, "The subpoena requests documents relevant to the Committee's investigation into Russian interference with the 2016 elections."
The senators said the documents are the same as those first requested from Flynn on April 28. But through his legal counsel, Flynn declined to cooperate with the committee's request.
Politico reports that Flynn's attorneys told the committee that the former general would not cooperate with the investigation unless he was granted immunity.
Flynn was fired by Trump in February after published reports that the national security adviser had misled Vice President Pence about his discussions with the Russian ambassador to the United States.
Flynn's contacts with the Russian government are also being examined by the FBI's investigation of possible links between Trump campaign officials and Russian meddling in the elections. The status of that probe is unclear in the wake of Trump's firing of FBI chief James Comey on Tuesday.