WASHINGTON (CNN) -- Former Arkansas Gov. Mike Huckabee, a GOP presidential candidate and a Southern Baptist minister, said Tuesday he will not attend a Baptist conference next January organized by former President Jimmy Carter, following Carter's criticisms that the Bush Administration is the "worst in history."

"I'm deeply disappointed by the unusually harsh comments made in my state this past weekend regarding President Bush, and feel that it represents an unprecedented personal attack on a sitting president by a former president which is unbecoming the office as well as unbecoming to one whose conference is supposed to be about civility and bringing people together," Huckabee said in a statement.

"President Carter violated an unspoken code that you don't make personal attacks on others who currently hold the job -- you just don't," he added.

Huckabee said he had originally agreed to attend the Baptist Covenant Program Celebration but changed his mind after learning of Carter's comments and seeing roster of speakers that he claims indicate the conference has a political agenda. Both former Presidents Carter and Clinton are slated to speak at the event.

Carter was quoted Saturday in the Arkansas Democrat Gazette as saying, "I think as far as the adverse impact on the nation around the world, this administration has been the worst in history." He later said he was only comparing the Bush administration's policy with that of the Nixon administration -- not every presidential administration in American history.