His comments come several days after Bharara commented about Flynn following reports that his lawyers had ended an information-sharing agreement with Trump's attorneys amid the probe into Russia's alleged interference in the US election.
Speculation about Flynn cooperating with Mueller's probe spiked last month when the special counsel hit former Trump campaign chairman Paul Manafort with an indictment that included money laundering allegations.
Lawyers for Flynn, President Trump's one time national security adviser, notified the president's own lawyers that they could no longer discuss the special counsel's investigation into Russian meddling in the USA election and possible collusion with the Trump campaign.
Flynn resigned as national security adviser this past February, less than a month into Trump's first term, when it was revealed that he had lied about conversations he'd had with Russian officials about potential sanctions relief. Federal investigators could be interested in the lobbying work that the men did in Turkey and in a December 2015 paid speech that the elder Flynn gave in Moscow at an event celebrating the Kremlin-funded television network RT.
The visit comes on the heels of reports, confirmed by the president's attorneys, that Flynn's lawyers had stopped communicating with the president's legal team regarding the criminal investigation. President Trump's personal attorney, Jay Sekulow, could not be reached for comment either.
But the departure from the agreement, according to Bill Mateja, a former Justice Department prosecutor, "is a clear sign that Michael Flynn is negotiating with the special counsel". "Also, prosecutors accept cooperation only if you can provide 'substantial assistance'".