In court documents and at a hearing where former National Security Advisor Mike Flynn entered a guilty plea for lying to the FBI, Special Counsel Robert Mueller’s team said that other officials in President Trump’s transition team were aware of and even directed Flynn’s backchannel communications with the Russian ambassador to the United States before Trump’s inauguration.

Flynn has now admitted that in a voluntary Jan. 24 interview with FBI he made false statements about a push by the Trump transition team to persuade officials from a foreign government to delay or defeat a United Nations Security Council vote on a resolution to condemn Israeli settlements. Flynn also has admitted he lied to FBI agents about a previously reported conversation he had with the ambassador, Sergey Kislyak, on Dec. 29 about sanctions the Obama administration was imposing on Russia at the time.

In both instances, Mueller alleged that at least another member of the Trump transition team was involved in Flynn’s plans to talk to Kislyak about the UN vote and the sanctions. The allegations undermine the response offered Friday by White House attorney Ty Cobb to news of Flynn’s guilty plea. “Nothing about the guilty plea or the charge implicates anyone other than Mr. Flynn,” Cobb said in a statement before the full range of Mueller’s allegations became public.

According to prosecutors, after Egypt submitted the UN resolution on Israeli settlements on Dec. 21, “a very senior member” of Trump’s transition team “instructed” Flynn to “contact officials from foreign governments, including Russia, to learn where each government stood on the resolution and to influence those governments to delay the vote or defeat the resolution.”

Flynn went on to discuss the vote with Kislyak on Dec. 22, and informed him that Trump’s incoming administration opposed it, according to prosecutors. Kisylak informed him the next day that Russia would not vote against the resolution, Mueller’s team said.

About a week later, as the Obama administration was getting ready to impose sanctions on Russia related to its interference in the 2016 election, Kislyak reached out to Flynn. The next day, Dec. 29, according to prosecutors, Flynn called a senior presidential transition team official who Mueller dubs the “PTT official.” The official, who was at Mar-A-Lago with other members of Trump’s transition team, discussed with Flynn what he should communicate to Kislyak, prosecutors said.

“The PTT official and Flynn also discussed that the members of the presidential transition team at Mar-A-Lago did not want Russia to escalate the situation,” Mueller’s court documents said.

Flynn called Kislyak immediately after his call with the official, where he asked that Russia not escalate the situation in its response to the sanctions, according to prosecutors. Flynn spoke to the transition official shortly thereafter, according to prosectors, to debrief the official on the call with Kislyak.

Kislyak called Flynn again on Dec. 31 to inform him Russia would not escalate its response, and after the call, “Flynn spoke with senior members of the Presidential Transition Team” about his conversations with the ambassador about the sanctions, the Mueller filing said.

The latest moves by Mueller add significant details to what we know about the Trump team’s backchannel diplomacy push during the UN vote and Flynn’s sanctions-related conversations with Kislyak, which led to his firing in February.

The Trump transition team’s scrambling to interfere with the Dec. 23 U.N vote had been reported more broadly by Foreign Policy. According to the magazine, the transition team begged Obama’s State Department to hand over the contact information of the foreign officials representing the countries involved in the vote (the State Department declined, according to FP).

Former South Carolina Gov. Nikki Haley, who would go on to be Trump’s UN envoy, called Obama’s UN ambassador Samantha Power on both her office and cell phone (Power did not respond, according to FP).

Foreign Policy also reported that Flynn reached out to officials from Uruguay and Malaysia about the vote, but in Mueller’s documents, Flynn also admits that Russia was part of his outreach efforts.

Flynn’s sanctions conversation with Kislyak was initially reported by the Washington Post and the New York Times; an official told the Post that “Kislyak was left with the impression that the sanctions would be revisited at a later time.”

The revelations on Friday go a step further, by detailing Kislyak’s response to Flynn’s request. Kislyak had also denied discussing sanctions with Flynn.

The biggest bombshell, however, is that Flynn was by no means a rogue freelancer in his efforts to undermine the Obama administration’s diplomacy; by Flynn’s own admission, other members of Trump’s transition team had condoned and even encouraged his backchannel communications.

Read Flynn’s statement of offense, filed by Mueller’s team, below: