President Trump blasted Democrats for funding the creation of a dossier containing salacious allegations against the president just one day after the revelation that Hillary Clinton's presidential campaign and the Democratic National Committee paid for the controversial document.

"I think it's very sad what they've done with this fake dossier. It was made up," Trump told reporters at the White House as he departed for Texas on Wednesday.

The so-called "Trump dossier" was compiled by an opposition research firm, Fusion GPS, during the 2016 race and alleged, among other things, Russians obtained compromising material on Trump and Trump's associates colluded with Russians during the race.

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Many of the claims contained in the dossier have not been substantiated, and those that have been are reportedly unrelated to claims of Russian collusion.

"Hillary Clinton always denied it. The Democrats always denied it, and now only because it's going to come out in a court case, they said, yes they did it," Trump said on Wednesday.

Indeed, the House Intelligence Committee had filed a subpoena to Fusion's bank in an effort to learn who paid for the dossier. Although Fusion had asked a judge to prevent the subpoena, the identity of the funding source still emerged Tuesday evening in a Washington Post report.

DNC officials said the current chairman, Tom Perez, was unaware the DNC had agreed to pay for a portion of the dossier's costs. Clinton's lawyer, Marc Elias, who entered into the agreement with Fusion on behalf of the Clinton campaign and the DNC, had previously denied to reporters that he was involved with the creation of the dossier.

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"It's a very sad commentary on politics in this country," Trump said.