Former Trump campaign chairman Paul Manafort met with Wikileaks founder Julian Assange in London multiple times, starting in 2013, including around March 2016, near the time that Manafort had been named the campaign’s convention manager, the Guardian reported Tuesday.

The bombshell report, citing unnamed sources, comes the morning after special counsel Robert Mueller accused Manafort of breaching his plea agreement by lying to investigators. Mueller has already indicted Russians accused of hacking the DNC and other Democratic individual and entities, whose emails were released by Wikileaks and other websites in the lead-up to the 2016 election.

Manafort issued a statement via his spokesman that said the story “story is totally false and deliberately libelous.”

“I have never met Julian Assange or anyone connected to him. I have never been contacted by anyone connected to Wikileaks, either directly or indirectly,” the statement said. “I have never reached out to Assange or Wikileaks on any matter.”

The Guardian report says it’s not clear why Manafort and Assange met in 2013, which is when Manafort was lobbying for a pro-Russian political party in Ukraine. Two sources told the Guardian that Manafort visited Assange, who had sought asylum in the Ecuadoran embassy in London, again in 2015. Manafort returned around March 2016, a “well-placed source” told the Guardian, which reported the meeting last around 40 minutes. Manafort’s visits to the embassy were not logged, as is typical practice, Ecuadorean sources told the Guardian.

The Guardian also reviewed flight records that showed that Manafort, sometimes, flew through London to get to Kiev, where his Ukrainian lobbying operation was based.

Manafort has denied any involvement in Russian meddling in the 2016 election and called claims about any connection to the Wikileaks hacks “100% false.” None of the charges Mueller has brought against Manafort so far have tied him explicitly to Russia’s interference efforts. The Guardian report said that his lawyers declined to answer the Guardian’s questions about its latest reporting. Manafort’s statement said that the Guardian “proceeded with this story even after being notified by my representatives that it was false.”

Wikileaks also denied the report on Twitter.

Remember this day when the Guardian permitted a serial fabricator to totally destroy the paper’s reputation. @WikiLeaks is willing to bet the Guardian a million dollars and its editor’s head that Manafort never met Assange. https://t.co/R2Qn6rLQjn — WikiLeaks (@wikileaks) November 27, 2018

An attorney for Assange also told CNN that ” no such meetings took place” and that they have had “no contact with the Mueller investigation.”

Prosecutors are seeking to move along with Manafort’s sentencing proceedings and said in a court filing Monday that they would detail for the court ahead of his sentencing “the nature of the defendant’s crimes and lies, including those after signing the plea agreement.”