(Reuters) - Former U.S. national security adviser Michael Flynn gave Special Counsel Robert Mueller information about attempts by people tied to the Trump administration and Congress to obstruct the Russia investigation, court documents released on Thursday showed.

Former U.S. national security adviser Michael Flynn departs after his sentencing was delayed at U.S. District Court in Washington, U.S., December 18, 2018. REUTERS/Joshua Roberts

The documents revealed for the first time sections that had originally been blacked out before last month’s release of Mueller’s report on his probe into Russia’s meddling in the 2016 election. The new disclosures were made at prosecutors’ request.

Flynn “informed the government of multiple instances, both before and after his guilty plea, where either he or his attorneys received communications from persons connected to the Administration or Congress that could have affected both his willingness to cooperate and the completeness of that cooperation,” Mueller wrote in a memo originally submitted ahead of Flynn’s planned sentencing on Dec. 18, 2018.

“The defendant even provided a voicemail recording of one such communication. In some instances, the SCO was unaware of the outreach until being alerted to it by the defendant,” he wrote, using the acronym for the Special Counsel’s Office.

U.S. District Judge Emmet Sullivan, who is overseeing Flynn’s case, further ordered the government to disclose transcripts of the voicemail recording and of Flynn’s conversations with Russian officials by May 31, and an unredacted version of the sections of Mueller’s report relating to Flynn.

Flynn pleaded guilty to lying to FBI agents about his December 2016 conversations with Sergei Kislyak, then Russia’s ambassador in Washington, about U.S. sanctions imposed on Moscow by the administration of Trump’s Democratic predecessor Barack Obama. The conversations took place between Trump’s November election victory and his inauguration in January 2017.

Flynn had been scheduled to be sentenced on Dec. 18 but the judge fiercely criticized the retired U.S. Army lieutenant general for his actions and delayed his sentencing until after he had finished helping prosecutors with other probes.

Mueller has asked for the judge not to sentence Flynn to prison given his substantial cooperation.

Flynn is still cooperating with prosecutors in the Eastern District of Virginia against his former business partner, Bijan Rafiekian, who was indicted on allegations of unregistered lobbying on behalf of Turkey. Rafiekian has pleaded not guilty and will take his case to a trial scheduled to begin in July.

Mueller completed his investigation in March. While he did not find that there was a conspiracy between Moscow and the Trump campaign to influence the 2016 election, his report describes multiple actions Trump took to try to impede the investigation. The report stopped short of declaring Trump had committed a crime.