President Donald Trump’s former campaign manager, Paul Manafort, held multiple meetings with WikiLeaks founder Julian Assange around the time that Manafort was brought on to run Trump’s campaign, according to The Guardian. Assange has vehemently opposed the integrity of the report, calling for the editor of paper’s head.

Allegedly, the meetings occurred in 2013, 2015, and March 2016 at the Ecuadorian Embassy in London where Assange has taken asylum for the past few years. The last meeting reportedly took place months after Assange released thousands of hacked emails belonging to Democratic National Convention officials that were acquired by Russian intelligence officers. Manafort has repeatedly denied his involvement with DNC email hack, but this revelation could come under scrutiny by special counsel Robert Mueller and his investigation into Russian collusion in the 2016 presidential election.

An internal document from Ecuador’s intelligence agency identifies Manafort as one of the embassy’s “well-known guests,” also mentioning “Russians.”

Moments after the report was released, the WikiLeaks Twitter account called out The Guardian, claiming that the report was false. “Remember this day when the Guardian permitted a serial fabricator to totally destroy the paper’s reputation,” the tweet read. “Wikileaks is willing to bet the Guardian a million dollars and its editor’s head that Manafort never met Assange.”

Reached by The Verge, Paul Manafort strenuously denied any in-person meeting. “This story is totally false and deliberately libelous,” Manafort said. “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. I have never reached out to Assange or Wikileaks on any matter.”

Like Assange, Manafort said he was considering legal retaliation for the report. “We are considering all legal options against the Guardian who proceeded with this story even after being notified by my representatives that it was false,” he continued.

In a court filing released yesterday, the special counsel said that Manafort had breached his September plea agreement by lying about a “variety of subject matters.” Manafort’s defense lawyers have disagreed, but under the terms of the agreement, Manafort cannot withdraw his guilty plea.

It’s been a rough month for Assange, who, according to The Daily Beast, has been forced into isolation by the embassy’s staff as they attempt to force him out. Visitors have been turned away, and Assange’s pet cat is now missing. Earlier this month, a court filing was released “in error” that suggested that Assange was facing criminal charges in the US. The filing did not identify what the charges were or when the alleged crimes took place.

Update 3:34PM ET: Updated with statement from Paul Manafort.