FILE PHOTO: Former national security adviser Michael Flynn exits a vehicle as he arrives for his sentencing hearing at U.S. District Court in Washington, U.S., December 18, 2018. REUTERS/Jonathan Ernst

WASHINGTON (Reuters) - U.S. President Donald Trump said on Sunday he is considering a full pardon for his former national security adviser, Michael Flynn, who had pleaded guilty to lying to the FBI about dealings with Russia’s ambassador before Trump took office.

Flynn sought to withdraw the guilty plea in January, arguing that prosecutors violated his rights and duped him into a plea agreement. Trump said the FBI and Justice Department had “destroyed” Flynn’s life and that of his family, and cited an unspecified, unsubstantiated report that they had lost records related to Flynn.

“I am strongly considering a Full Pardon!” Trump said on Twitter.

Flynn was supposed to help cooperate with the government as part of his plea deal. But he later switched lawyers and tactics, arguing that prosecutors in the case had violated his rights and tricked him into lying about his December 2016 conversations with Sergei Kislyak, then Moscow’s ambassador in Washington.

The Department of Justice has repeatedly denied allegations of prosecutorial misconduct, and U.S. District Court Judge Emmet Sullivan rejected all of Flynn’s claims in December and set a sentencing date.

Shortly after that, Flynn filed the motion to withdraw his plea.

Flynn, who also previously led the Defense Intelligence Agency, served just 24 days in the Republican Trump administration before he was fired in January 2017.

He was one of several former Trump aides to plead guilty or be convicted at trial in former Special Counsel Robert Mueller’s investigation that detailed Moscow’s interference in the 2016 U.S. election to boost Trump’s candidacy, as well as numerous contacts between Trump’s campaign and Russia.