Special counsel Robert Mueller's team met with the author of the Russia dossier that contained scandalous allegations against President Trump some time during the summer, according to a report Thursday.

The information provided by the author and former British spy Christopher Steele may help Mueller and his team assess if contacts between the Trump campaign and potential Russian operatives resulted in collusion, CNN reported.

Although not publicly stated, the FBI and the U.S. intelligence community in 2016 regarded the dossier very seriously. Various intelligence agencies, especially the CIA and the FBI, regarded the dossier so seriously, they prevented it from being included in a publicly released report in January that discussed Russia's interference in the 2016 election to prevent revealing which parts of the dossier they had verified.

However, Trump has greatly downplayed the dossier and said it "was totally made-up stuff" to the New York Times.

Some aspects of the dossier — like communications between foreign nationals noted in the dossier — have been confirmed by officials; however, the majority of the scandalous allegations included in the document have not been verified.

Senate Intelligence Committee Richard Burr, R-N.C., expressed this week that Steele had dismissed requests to meet with the committee, and therefore, the credibility of the dossier was difficult to verify.

"The committee cannot really decide the credibility of the dossier without understanding things like, who paid for it? Who are your sources and sub-sources?" Burr said. "We're investigating a very expansive Russian network of interference in U.S. elections. And though we have been incredibly enlightened at our ability to rebuild backwards, the Steele dossier, up to a certain date, getting past that point has been somewhat impossible."

The dossier includes content originally intended to be used as opposition research during the GOP primaries by anti-Trump Republicans; however, Democrats got on board once Trump won the nomination in May 2016. Steele was hired during the summer of 2016 to join the Washington firm that had already started to gather information.

Mueller is investigating Russian interference in the 2016 election and whether the Trump campaign colluded with the Kremlin.