Kansas City, Mo ? A debate between two Kansas congressional candidates at a TV studio escalated after the taping ended Friday, participants said.

Accounts of the exchange involving Jeff Colyer, Adam Taff and their aides varied, especially over whose voice if anyone’s was raised.

Colyer, a surgeon, and Taff, a pilot, are seeking the Republican nomination in Kansas’ 3rd Congressional District in the Aug. 6 primary. The winner will face the incumbent, Democratic Rep. Dennis Moore, in November. The 3rd District includes most of Lawrence east of Iowa Street.

Taff and Colyer sat side-by-side Friday at a table at the studio of Kansas City public television station KCPT, answering questions from two TV reporters for a segment of “Kansas City Week in Review.” The 30-minute program is broadcast Friday nights and Sunday mornings.

When the taping ended, Colyer and Taff shook hands and that’s when the atmosphere became tense, people who were in the studio said in telephone interviews later Friday.

KCPT moderator Nick Haines, who conducted the questioning along with Dave Helling of Kansas City station KCTV, said he had turned away from the candidates when he heard someone say, “Don’t hit him.” About 20 people were in the studio at the time.

Haines said he could not tell whether the person was joking.

When he turned toward the candidates, Haines said, he saw Taff with his hand on Colyer’s shoulder.

“It was difficult to explain what was going on but it was not a pleasant exchange,” Haines said.

Aides then began to intervene, Haines said. A photographer said there was shouting.

“I told (Helling) to take Colyer and I’ll take Taff,” Haines said. “And we took them out of the studio by the hand.”

Haines said the forum had turned contentious in the final moments, with Taff questioning Colyer’s assertions about the nature of his surgical practice and his authorship of some books.

The dispute was unusual in a campaign that had seen little acrimony previously, Haines said.

“It’s interesting,” Haines said. “The candidates have been a little like wallpaper at other events. It was surprising to see them get so snippy.”

Colyer, in a telephone interview, said he had taken off his microphone and gone to shake Taff’s hand.

“He wouldn’t let go of my hand,” Colyer said, “and he grabbed my shoulder and wouldn’t let go and started yelling things. I said, ‘Adam, let’s keep it civil.”‘

Colyer said Taff “was trying to physically intimidate me, and I just stood my ground.”

However, Taff said the discussion was calm and that there were no raised voices.

“To even imply that I was doing anything intimidating would be a total mischaracterization,” he said.

Taff also said that when the two shook hands, Colyer told him that he needed to keep the campaign fair. Taff said he replied that Colyer had been slandering him and had attacked his character.

At issue, according to Taff as well as an official of Colyer’s campaign, was a so-called “push poll” conducted on Colyer’s behalf.

In push polls, voters typically are asked how their opinion of an opposing candidate would be influenced if they knew certain information about the individual. The idea is to “push” a voter’s opinion in a certain direction.

Candidates often complain that the information passed along by the opponent’s pollster is misleading or inaccurate.

Taff said voters who were contacted for the Colyer push poll were given erroneous information about how often Taff has voted in the past.