Washington, Dec 12 (IANS): US President Donald Trump's former National Security Advisor Michael Flynn has asked a federal judge to spare him from prison time, saying that his cooperation with Special Counsel Robert Mueller's probe "was not grudging or delayed".

"Rather, it preceded his guilty plea or any threatened indictment and began very shortly after he was first contacted for assistance by the Special Counsel's Office," Flynn's defence team wrote in a memo on Tuesday.

The former official has also offered to do 200 hours of community service, CNN reported.

Judge Emmet Sullivan of the US District Court for the District of Columbia is scheduled to sentence Flynn on December 18.

Last week, Mueller told the court that Flynn has provided "substantial assistance" to the investigation and should be spared from going to prison.

Court filings revealed that Flynn met 19 times with Mueller's team and other Justice Department offices, suggesting vast cooperation.

Flynn is the highest-ranking Trump official to face charges in the Mueller probe.

He pleaded guilty in December 2017 to lying to the Federal Bureau of Investigation (FBI) about his contacts with the then-Russian ambassador to the US.

Flynn initially denied but eventually said that they had discussed sanctions and a UN resolution during the presidential transition.

The saga led to his early exit from the White House.

Flynn's likely sentence is between zero and six months in prison.