But the chairman began signaling this week that if Trump surrogates did not turn over requested materials to the committee by Tuesday - a deadline that some missed - he and Vice Chairman Mark Warner, D-Va., might begin issuing subpoenas.
Mr Flynn's Russian Federation ties are also being scrutinised by the FBI as it conducts a similar investigation. Mark Warner, the committee's Democratic vice chairman, issued a joint statement saying the panel chose to issue the subpoena after Flynn, through his lawyer, declined to cooperate with an April 28 request to turn over the documents.
It is the first subpoena the committee has announced in the course of its Russian Federation investigation - a step Chairman Richard Burr, R-N.C., was long reticent to take. The other three are former campaign foreign policy adviser Carter Page, former campaign chairman Paul Manafort and former adviser Roger Stone.
Sergei Lavrov, Russian foreign minister, jokes about Comey firing
They also discussed Trump's "desire to build a better relationship between the United States and Russian Federation ". Trump made the comments during a surprise Oval Office meeting with former Secretary of State Henry Kissinger .
"The subpoena requests documents relevant to the Committee's investigation into Russian interference with the 2016 election", Burr and Warner said in a joint statement.
Flynn was sacked by Trump after less than one month on the job. He was forced to resign in February as Trump's national security adviser for failing to disclose the content of his talks with Sergey Kislyak, Russia's ambassador to the United States, and then misleading Vice President Mike Pence about the conversations.
Flynn is one of four former aides to President Donald Trump that the intelligence committee has requested documents from.
Erik Paulsen calls for independent investigation after Trump's firing of Comey
But we know from his public statements that Trump does not share any of Rosenstein's concerns that Comey was unfair to Clinton. It only invites further discussion of whether Comey's misdeeds actually, and unfairly, gave the election to Trump.
Page has already replied to the committee numerous times, saying he will not cooperate with their request until Senate investigators ask former President Barack Obama's administration for his communications - an allusion to Page's accusation that he was targeted by the Obama administration.
Flynn is also under investigation for business dealings he had with clients tied to foreign governments.
The Turkish payments under scrutiny are part of $530,000 worth of lobbying and investigative work that Flynn's company, Flynn Intel Group, performed for a Turkish businessman.
Bucks, Game 6: Just close it out
NOTES: Middleton missed practice with an illness that has been bothering the Bucks' second-leading scorer (14.7 points) all week. Here are some things that can not happen tonight if the Bucks hope to force a Game 7: Giannis can not score under 20 points.
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