DES MOINES — The Republican Party’s leader in Iowa’s biggest county says he’s had enough with the negative advertisements blanketing the airwaves across the state.

Kevin McLaughlin, chairman of the Polk County Republican Party, called for a moratorium on negative advertisements in an interview Monday, and said he planned to issue a formal call at a news conference later this week.

“It’s like drinking salt water,” McLaughlin said. “When you drink salt water, you get a short-term benefit, but long-term it’s worse for you. That’s what we’re doing here, and it’s got to stop.”

McLaughlin said the ads were deepening what had been a natural splintering of the party’s base during the hotly contested presidential primary campaign. He added that he fears the rift could cause irreparable harm to the eventual Republican nominee in next year’s general election campaign against President Obama.

“They create deep rifts at the base of the party, which make it harder to pull the party together by the general election,” McLaughlin said. “That’s going to be a huge problem for us, and I don’t think people are paying enough attention to that.”

McLaughlin, who is unaligned in the race, did not single out any campaign or political action committee. Restore Our Future, a PAC financed by supporters of former Massachusetts governor Mitt Romney, has spent more than $2 million airing ads attacking former House speaker Newt Gingrich. The campaigns of Texas Gov. Rick Perry and Rep. Ron Paul (Tex.) also have aired attack ads against Gingrich and other candidates.

McLaughlin is the top party official in Polk County, which includes the state capital of Des Moines and is the most populous of Iowa’s 99 counties. Neither he nor any other GOP official has the authority to dictate the kinds of advertisements campaigns or political groups put on the air.