WASHINGTON — President Trump and fellow Republicans latched onto revelations tying Hillary Clinton’s presidential campaign to a dossier of allegations about his ties to Russia, saying Wednesday that it was a ‘‘disgrace’’ that Democrats had helped pay for research that produced the document.

‘‘It’s just really — it’s a very sad commentary on politics in this country,’’ Trump said in addressing reporters one day after news reports revealed that the Clinton campaign and the Democratic National Committee, for several months last year, helped fund research that ultimately ended up in the dossier.

The document, compiled by a former British spy and alleging a compromised relationship between Trump and the Kremlin, has emerged this year as a political flashpoint. Law enforcement officials have worked to corroborate its claims. James Comey, FBI director at the time, advised Trump about the existence of the allegations, and the ex-spy who helped assemble the document, Christopher Steele, has been questioned as part of an ongoing probe of possible coordination between Russia and the Trump camp.

Meanwhile, the editor of Wikileaks confirmed that the group was approached by a data firm working for Trump’s campaign during the 2016 election.

Julian Assange said on Twitter that Cambridge Analytica reached out to his group before last November, but Wikileaks rejected the company’s ‘‘approach.’’ Assange didn’t specify the content of that approach.

He issued the tweet after a news website, The Daily Beast, reported that Cambridge Analytica CEO Alexander Nix reached out to Assange during the presidential campaign about the possible release of 33,000 of Hillary Clinton’s missing e-mails. Those e-mails have never been publicly released.

Robert Mercer, a billionaire Trump supporter, is a backer of Cambridge Analytica. Former White House strategist Steve Bannon served as a vice president at the company before joining the administration.

Trump has derided the dossier as ‘‘phony stuff’’ and ‘‘fake news’’ and portrayed himself Wednesday as an aggrieved party, posting on Twitter a quote he said was from Fox News that referred to him as ‘‘the victim.’’ The new disclosure about the dossier’s origins is likely to fuel complaints by Trump and his supporters that the document is merely a collection of salacious and uncorroborated claims.

‘‘Well, I think it’s very sad what they’ve done with this fake dossier,’’ Trump said Wednesday, adding without elaboration that ‘‘they paid a tremendous amount of money.’’

A person familiar with the newly disclosed dossier matter, speaking on condition of anonymity to discuss confidential client matters, the funding arrangement was brokered in the spring of 2016 by a law firm representing the Clinton campaign and the DNC.