Updated

Sen. Jim Bunning (search), a hard thrower during his Hall of Fame baseball career, fired at his Democratic opponent Wednesday, accusing him of spreading "disgusting" rumors that the incumbent is mentally incompetent.

"I think that's the lowest of the low of anybody who I have ever run against," said the 72-year-old Republican, who charged that Daniel Mongiardo's (search) campaign conducted a "push-poll" that asked respondents: "Did you hear that Jim Bunning was mentally incompetent to run for the U.S. Senate?"

"The rumors that have been spread by my opponent about my health are disgusting," Bunning said during a campaign stop here. "People who know me know the truth."

Contacted by The Associated Press, Mongiardo denied Bunning's accusation as "just another absurd comment," but questioned what he called his opponent's "bizarre conduct."

During the campaign, Bunning has compared Mongiardo's appearance to that of one of Saddam Hussein's (search) sons and alleged Mongiardo's staffers assaulted his wife at a political picnic, leaving her "black and blue." Mongiardo has denied the accusations.

Mongiardo said it was only natural or voters to question: "Why is he acting this way? And I think that it's just natural for people to start talking about what could be the reason. But I didn't start that."

Last week, the state's largest newspaper, The Courier-Journal of Louisville, endorsed Mongiardo and wrote an editorial questioning Bunning's "suitability" for office.

"Has Sen. Bunning drifted into territory that indicates a serious health concern?" the editorial asked.

Bunning has released letters from two doctors stating he is in excellent health and emphasized a rigorous campaign schedule. He said he visited 30 counties in August and will visit 30 more next week as part of a statewide bus tour. The senator also promised to serve the full six years if he's re-elected to a second term on Nov. 2.

Bunning held a double-digit lead in a poll published last month by the Courier-Journal. But Mongiardo, a surgeon and state senator from the Appalachian town of Hazard, has run a hard-charging campaign and claims the race has tightened considerably.

Boone County Judge-Executive Gary Moore, a Bunning supporter, said he detected no change in Bunning in recent months. He said Bunning's comments reflected the same "passion" he displayed on the pitcher's mound.

"Whether you are a friend or a foe, Jim Bunning speaks his mind," Moore said. "He is very forceful, very strong."