Paul Manafort, a political strategist and one of President Trump’s former campaign managers, met secretly with WikiLeaks founder, Julian Assange, in 2013, 2015, and 2016 at the Ecuadorian Embassy in London, where he is granted asylum, according to an anonymously sourced story in the Guardian.

The 2016 visit came during the spring, reportedly around the time Manafort joined the Trump campaign, and lasted for about 40 minutes, a source told the outlet. He was reportedly not registered as a visitor.

The source said the visit occurred “around March 2016.” Manafort joined the Trump campaign on March 29, 2016. His role was to corral delegates for Trump at the Republican National Convention before becoming campaign manager in May 2016.

The Guardian noted that WikiLeaks began releasing stolen Democratic National Committee emails “months later” yet did not say if Manafort had anything to do with them. The report acknowledged that “it is unclear why Manafort wanted to see Assange and what was discussed.” Manafort, 69, has denied any involvement in the theft of the emails.

The report does not say when Manafort visited the Ecuadorian embassy in 2013 or 2015. Sources told the Guardian that Manafort’s acquaintance with Assange goes back “at least five years, to late 2012 or 2013,” when Manafort was working in Ukraine as a lobbyist.

WikiLeaks slammed the story in a tweet, calling its publication the “day when the Guardian permitted a serial fabricator to totally destroy the paper’s reputation.” The company then bet the Guardian a “million dollars” and its editor’s job that Manafort never met Assange. It also began tracking edits to the story in subsequent tweets:

The president’s lawyer, Rudy Giuliani, also told NBC News that the allegation that Manafort met with Assange in 2016 was “fake news.”

The revelation of the visits in the media comes as special counsel Robert Mueller is reportedly focusing in on the role of Assange in investigating if Trump’s campaign colluded with Russia during the 2016 election.

Mueller has been reportedly examining long-time Trump associate Roger Stone’s connection to WikiLeaks. Stone famously tweeted on August 21, 2016, “It will soon the Podesta’s time in the barrel.” Emails stolen from former Hillary Clinton campaign chairman John Podesta were released by WikiLeaks on October 7, 2016.

Stone has said he got his information about WikiLeaks from associate Randy Credico, who is allegedly close to one of Assange’s lawyers, and that he did not know the source of the emails or that Podesta’s emails would be released, according to the Daily Caller.

In September, Manafort pleaded guilty to one count of conspiracy against the U.S. and one count of obstruction as part of a plea deal with the special counsel. In August, he was convicted of eight crimes tied to his lobbying work in Ukraine. He is currently in jail in Alexandria, Virginia.

On Monday, the special counsel team ended the plea deal and accused Manafort of lying to investigators, and moved to set a date for him to be sentenced. His attorneys say Manafort has been truthful and has not violated his deal.

Last week, a court filing that was accidentally released suggested that the Justice Department had secretly charged Assange with a criminal offense, but it was not clear what that alleged offense was or when it occurred.

This story has been updated.