American media and politicians have been in possession of versions of the 35-page report for months but, unable to corroborate its claims, had until now declined to publish it.
On Tuesday, after several media reported that Trump had been briefed on the allegations circulating about him, BuzzFeed news took the controversial step of publishing the dossier in full — while admitting it is “unverified.”
Here is what we know:
What is the Russia dossier?
The 35 pages consist of memos compiled before and after the November 8 election by a former British MI-6 intelligence agent who was paid to produce opposition research on the Trump campaign, first for a Republican rival of Trump and then later by Hillary Clinton’s Democratic campaign.
On Friday US intelligence chiefs, briefing Trump on allegations of Russian interference in the US election, also reportedly included a two-page summary of the most credible claims from the political research report.
That classified summary has been shown only to Trump, President Barack Obama, and a group of senators from the Senate Intelligence Committee.
BuzzFeed has published the entire 35-page document, noting that the allegations are all “unverified”.
What claims does it make?
The dossier includes unsubstantiated claims that Russians possess videos involving prostitutes, filmed during a 2013 visit by Trump to a luxury Moscow hotel for the Miss Universe contest, supposedly as a potential means for blackmail.
It also alleges that Trump advisors including his lawyer Michael Cohen maintained regular contact with Russian officials and others linked to Russian intelligence during the election and have been exchanging information for “at least” eight years.
The former British spy behind the report, who had long experience in Russia, based on it what he heard from his contacts. It is not known if any of the claims in the memos are true.
The FBI has been investigating the claims and Democrats are demanding an inquiry into allegations Trump’s team met with Russian officials during the campaign.
How has Trump responded?
Trump has angrily dismissed the report as a fabrication, with the president-elect’s spokesman slamming BuzzFeed’s decision to publish it as “outrageous and highly irresponsible.”
Trump said he was the victim of “fake news” while praising other US media who refrained from printing the report’s most lurid allegations.
“It’s all fake news. It’s phony stuff. It didn’t happen. And it was gotten by opponents of ours, as you know,” he told a press conference in New York.
Trump’s lawyer Cohen — who was alleged to have met Russian operatives in the Czech capital in August — also denied having ever visited Russia or Prague.
What are Trump’s known ties to Russia?
Trump reiterated at Wednesday’s news conference that he has “no loans, no dealings, and no current pending deals” with Russia, when asked if the country could have any leverage over him.
Several Trump advisors have longstanding links to the country, however.
Paul Manafort, his first campaign manager, was previously a consultant to Moscow-backed former Ukraine prime minister Viktor Yanukovych, and also worked with Russian oligarchs with Putin ties.
Another Trump advisor, Carter Page, was previously a Moscow-based investment banker and visited Moscow in July and then in December after the election for what he called private affairs.
Trump’s nominee for National Security Advisor, Michael Flynn, was paid by Russian broadcaster RT to join a gala celebration in Moscow last year, where he sat at a banquet table with Putin.
The president-elect himself has a long history of seeking closer links with Russia. He sought since the 1990s to build a luxury apartment and hotel building in Moscow, but has never been able to seal a deal.
When visiting Moscow in 2013 for the Miss Universe contest, Trump said he hoped to build bonds with Putin. He did not meet the Russian strongman, but did meet a top Putin aide.
Court documents also show that Russian investment helped fund a major Trump-backed New York building, the 46 floor Trump Soho luxury apartment development built in the mid-2000s.