The fired US national security adviser will refuse to hand over documents to a Senate panel investigating alleged Russian meddling in the US election.
Michael Flynn reportedly plans to invoke his Fifth Amendment right against self-incrimination on Monday.
The Senate Intelligence Committee is probing possible links between the Trump campaign and Kremlin.
Mr Flynn quit in February, after it emerged he lied about the nature of his contacts with the Russian ambassador.
The committee issued a subpoena – a legal summons – two weeks ago to obtain the documents.
My Flynn’s lawyer had previously demanded legal immunity from “unfair prosecution” in order to cooperate with the committee.
Last week the committee’s chairman Senator Richard Burr told reporters that Mr Flynn was “not cooperating” with the investigation, adding that they had not received “a definitive answer” on whether he would testify.
Mr Flynn is also being investigated by the Department of Defense, after it was revealed that he received payments from Russia and Turkey shortly after leaving the Pentagon.
He is also at the centre of an FBI investigation into possible collusion between the Trump presidential campaign and Russia.
Former FBI director Robert Mueller was appointed last week to lead the FBI investigation following Mr Trump’s firing of the law enforcement agency’s director, James Comey.
If Mr Flynn continues to refuse to comply with Senate investigators, it is thought they could vote to hold him in contempt of Congress, or even refer his case for possible criminal charges.