Donald Trump’s former campaign chairman Paul Manafort lied to the FBI and to the special counsel’s office on five different matters after entering an agreement to cooperate with prosecutors, Robert Mueller alleged in a court filing on Friday.

Manafort tried to hide the fact that he had contact with “an administration official” inside the White House as late as May 2018, according to Mueller’s filing, which was partially redacted and did not specify what Manafort had discussed with the White House.

Manafort was convicted earlier this year of eight felony fraud charges and is fighting additional charges relating to his former career as a political consultant in the Soviet bloc – work that overlapped with his time as chairman of the Trump campaign in the spring of 2016.

Former campaign officials and Trump aides are simultaneously under pressure from Mueller, who is investigating alleged collusion between the campaign and Russian operatives in the run-up to the election.

Separately on Friday, Mueller filed a memorandum describing how the former Trump aide Michael Cohen had cooperated with his office in describing his own contacts with White House officials on matters close to the “core” Mueller investigation.

“Manafort told multiple discernible lies – these were not instances of mere memory lapses,” Mueller said in his Friday submission to the court, citing “independent documentary and testimonial evidence” as well as electronic records obtained from Manafort.

Mueller alleged that Manafort also lied about his interactions with Konstantin Kilimnik, a former business partner in Ukraine; about Kilimnick’s participation in an alleged conspiracy to tailor the testimony of two witnesses; about a wire transfer to a firm working for Manafort; and about information pertinent to another justice department investigation, the details of which were undisclosed.

Sarah Sanders, the White House press secretary, told reporters the filing said “absolutely nothing about the president” and “even less about collusion”. Portions of the filing were redacted.

In sum, Manafort sat for 12 meetings with special counsel, including three prior to the plea agreement, Mueller said. He has testified twice before a federal grand jury.

Mueller submitted the document to explain why a cooperation agreement with Manafort reached in September had fallen apart. Manafort denies lying to Mueller, but both sides have requested that the court not delay sentencing Manafort on multiple fraud convictions.

Manafort was chairman of the Trump campaign for five months in the spring of 2016, a period Mueller has scrutinized closely. The special counsel is investigating alleged collusion between the Trump campaign and Russians tampering in the presidential election.

Manafort, 69, was convicted in August of five counts of tax fraud, two counts of bank fraud and one count of failure to report a foreign bank account. The charges carry a maximum sentence of decades in prison.