Michael Flynn to take the 5th Amendment and decline Senate subpoena

— -- Former national security adviser Michael Flynn will invoke the Fifth Amendment and refuse to honor a Senate committee's subpoena request for documents relating to Russian interference in the 2016 presidential election, a source close to Flynn confirmed for ABC News.

The Fifth Amendment gives an individual the right to avoid self-incrimination.

"He will not be producing the documents they sought. He is entitled to decline, pursuant to the Fifth Amendment," a source close to Flynn told ABC News.

To date, Flynn is the only Trump associate whom the Senate has subpoenaed.

Legal experts told ABC News that Fifth Amendment rights apply not just to someone seated at a witness table. It also allows the individual to decline to produce documents that could be incriminating.

The Senate Intelligence Committee subpoenaed Flynn's personal documents on May 10, after he declined to cooperate with its April 28 request in relation to the panel's investigation of Russian interference in the 2016 election and possible ties to Trump associates.

Before the April request, Flynn said through a statement from his lawyer that he wouldn't submit himself to questioning from the committee "without assurances against unfair prosecution."

President Trump then weighed in on Twitter, saying that Flynn was right to ask for immunity "in that this is a witch hunt (excuse for big election loss), by media & Dems, of historic proportion!"

White House press secretary Sean Spicer said on March 31 that Trump "believes that Mike Flynn should go testify ... go get it out there, do what you have to do."

Last week Senate Intelligence Committee Chairman Richard Burr, R-N.C., said, "Gen. Flynn's lawyers said that he would not honor the subpoena, and that's not a surprise to the committee," but Burr's office later put out a statement saying Flynn's attorneys had not yet responded.