Michael Flynn. Photo: Reuters
The office investigating alleged Russian collusion in the 2016 US election has said it is not pursuing a jail sentence for ex-national security adviser Michael Flynn.
Special Counsel Robert Mueller's office said Mr Flynn had provided "substantial assistance" in its investigation.
Mr Flynn has admitted one count of lying to the FBI.
He is the only member of the Trump administration so far to plead guilty as a result of the investigation.
President Donald Trump has called the investigation a witch hunt and denies there was any collusion between his team and Russian officials to try to secure his election victory.
Why has the memo been released?
Mr Mueller's office released the memo as guidance to the judge who will sentence Michael Flynn.
He is due to be sentenced in the US District Court for the District of Columbia on 18 December.
Mr Flynn has pleaded guilty to one count of making materially false statements to the FBI.
He admitted that he discussed lifting US sanctions on Russia with the Russian ambassador to Washington before Mr Trump took office, and that he lied to the US vice-president about that conversation.