The head of the Missouri Republican Party on Tuesday asked Republican National Committee Chairman Reince Priebus to appoint a task force to investigate what he called “racially divisive ads and robocalls” critical of state Sen. Chris McDaniel in the Republican runoff for U.S. Senate in Mississippi, marking the latest instance of lingering intra-party discord following Sen. Thad Cochran’s narrow victory over McDaniel last month.

Missouri GOP Chairman Ed Martin e-mailed letters to Priebus and RNC members Tuesday afternoon expressing concerns over ads reported by Britain’s Daily Mail newspaper that sought to link McDaniel to a Ku Klux Klan ally, suggested that the tea party has “racist” ideas and warned that a vote for McDaniel could mean losing food stamps and other government programs.

Martin’s concerns came a day after Sen. Ted Cruz (R-Tex.) slammed the “D.C. machine” for “racially charged false attacks” against McDaniel. And they arrived as McDaniel’s campaign was gearing up to challenge the results of the election, which were certified Monday.

“Last week, the Clarion-Ledger was able to tie McDaniel’s campaign to an ally of the Ku Klux Klan,” said the narrator of one of the ads reported by the Daily Mail, an apparent reference to a newspaper report about a McDaniel supporter named Carl Ford, who reportedly had Klan ties. The same narrator said in another commercial that “if the tea party with their racist ideas win, we will be set back to the ’50s and ’60s.”

Martin, who said he was neutral during the primary and runoff, said his concern is that Republican National Committee member Henry Barbour could be partially responsible for the ads. The Daily Mail report suggested that Barbour, who ran a pro-Cochran super PAC, could have ties to the group that ran the ads, Citizens for Progress. The group has no record at the Federal Election Commission.

“We cannot object to the Left smearing conservatives with such labels if we do not rebuke those on our side who sink to such tactics,” Martin wrote in his letter, which was obtained by The Washington Post.

In an interview, Barbour said his group ran no racially charged radio ads and that he has no idea who sponsored the commercials cited in the Daily Mail report, which he said he has not heard.

“We ran no radio ads that had anything to do with the KKK or race, or anything like that,” Barbour said.

Martin asked Priebus to “appoint a special committee of RNC members to investigate this matter and report to us at our August 7th Members meeting before the August 8th general RNC meeting.” Martin said in a telephone interview that he already had received a response from one RNC member volunteering to join the special committee.

An RNC spokeswoman did not immediately respond to requests for comment.

Cochran and his allies courted Democratic voters, including many African Americans, during the runoff campaign. The strategy apparently worked, based on a Washington Post analysis that showed that in 24 counties with a majority black population, turnout increased an average of 40 percent over the primary. In the state’s 58 other counties, the increase was 16 percent.

Cochran was certified as the winner of the June 24 runoff by the Mississippi Republican Party on Monday. But McDaniel’s campaign signaled that it is moving toward challenging the results based on allegations of voter fraud. A spokesman for McDaniel said the campaign would not present its evidence until it lodged its complaint with the state GOP.