House Minority Leader Nancy Pelosi (D-CA) has supported Senate Majority Leader Harry Reid's allegation that Mitt Romney avoided paying taxes for years, giving her imprimatur to a charge that Romney's campaign has dismissed as baseless slander.

Reid said last week that Romney may have paid no taxes for a decade, attributing the electrifying claim to a nameless employee of Bain Capital, the venture capital firm Romney used to run. The Romney camp immediately rejected the statement and Romney questioned the source of Reid's information, saying the Nevada Democrat had to "put up or shut up" and name his confidante.

But Reid pressed on, saying that Romney could defuse the controversy by releasing more of his tax returns. The Obama campaign and its surrogates have continually pressured the presumptive Republican nominee to release more of his tax returns, using the issue to portray Romney as wealthy and out of touch.

Pelosi, the top Democrat in the House of Representatives, embraced that strategy in a Sunday interview with the Huffington Post.

"Harry Reid made a statement that is true. Somebody told him. It is a fact," Pelosi said. "Whether he did or not can easily be disposed of: Mitt Romney can release his tax returns and show whether he paid taxes."

The California Democrat did not explicitly endorse the idea that Romney had paid no taxes for a decade, focusing instead on the veracity of a Bain employee having told Reid that was the case. Romney has raised the possibility that someone in the White House leaked the charge for political gain.

Reid "wouldn't say this unless it was true that somebody told him that," Pelosi said.

Republican National Committee chairman Reince Preibus has responded to the burgeoning controversy by calling Reid a "dirty liar," a choice of words he refused to back down from.

"There's no triple down in blackjack, but I'll triple down on my comments from yesterday," Priebus said in an appearance on the program Fox and Friends. "It's just the truth. What else do you call somebody who goes onto the Senate floor and claims that someone hasn't paid taxes in ten years, a complete lie, and uses his official office to do it?"

When Romney released some tax returns in January, responding to pressure from his then-rivals for the Republican nomination, the documents revealed that he had paid an effective tax rate of 13.9 percent in 2010 despite pulling in some $21.7 million in personal income, much of it from investments.