Sen. Harry Reid

Republicans are accusing the Senate's Democratic leader of lying by passing along an anonymous claim that Mitt Romney hasn't paid taxes for 10 years.

Sen. Harry Reid said last week he had been told that by an investor in Romney's former firm, Bain Capital. But the Nevada Democrat hasn't offered any evidence to support the claim and even has said he's not sure it's true, reports The Associated Press.

GOP Sen. Lindsey Graham of South Carolina tells CNN's "State of the Union" that he thinks Reid is "lying about his statement of knowing something about Romney" and just "making things up" to divert the campaign from "the real issues."

Republican Party chairman Reince Priebus tells ABC's "This Week" that Reid is "a dirty liar."

Reid's spokesman could not immediately be reached for comment.