A rivalry between two Democratic presidential candidates has increased after one side claimed their campaign staffer was shoved and insulted with homophobic slurs by a staff member from the other candidate’s campaign.

Managers of Howard Dean’s presidential campaign have complained to aides to rival Rep. Dick Gephardt, D-Mo., about an episode they said occurred at a Gephardt campaign event.

Sarah Leonard, Dean’s Iowa spokeswoman, said a Dean campaign staffer attended a Gephardt event in Des Moines Tuesday. The staffer was pushed, grabbed and subjected to verbal abuse containing homophobic slurs by Gephardt staffers, she said.

“At the least, our staff person deserves an apology, but we urge the Gephardt campaign to find the person and fire them,” Leonard said. “A homophobic slur that was used against our campaign person should never cross anyone’s lips, and when it does, actions should be taken.”

Bill Burton, Gephardt Iowa communications director, denied the episode took place. Burton said a Dean staffer did attend a Gephardt event Tuesday, but he was acting disruptive and inappropriate.

“We simply asked him to leave the event and he did,” Burton said. “I don’t feel the members of our campaign acted inappropriately.”

Burton said claims against the Gephardt campaign were unsubstantiated, due to lack of proof and other witnesses.

“There were 100 people at Gephardt’s speech, including 20 members of the media,” he said. “In fact, the kid who was asked to leave was carrying a tape recorder and nobody has a lick of proof it happened.”

Members of the Dean campaign are standing by their allegations, and are expecting an apology from the Gephardt campaign.

“It’s outrageous for the Gephardt campaign to shrug this off and deny it,” Leonard said.

Joel Taylor, acting president of Cyclones for Dean, said he believed the event took place based on previous incidents between Gephardt staffers and Dean supporters.

“Back in late September, early October, one of the retired ladies in the Ames area who supports Governor Dean received several phone calls from the Gephardt campaign,” he said. “When she indicated her support for Dean, they were rude to her.”

Dean and Gephardt, who are locked at the top of Iowa polls, have taken aim at each other’s campaigns. New Iowa ads from the Dean campaign have added to the animosity between the two candidates.

On Oct. 23, one Dean advertisement targeted his rivals on Iraq. Dean said he opposed the war from the start and added, “The best my opponents can do is ask questions today that they should have asked before they supported the war.” Gephardt voted in favor of the resolution authorizing the war.

Gephardt has slung his own mud at his opponent, likening Dean’s views on Medicare to those of President Bush. He also blasted the former Vermont governor for his stance on NAFTA and trade relations with China.

Polls in Iowa indicate the two candidates are in a league of their own. According to a Zogby poll released Oct. 22, Gephardt holds the backing of 22 percent and Dean holds 21 percent. The next closest competitor was John Kerry with nine percent.

— The Associated Press contributed to this article.