The son of a Republican Senate candidate in Wisconsin has apologized after he told a joke about sending Barack Obama to Kenya, suggesting that agrees with the so-called birthers who do not believe that the president is a U.S. citizen.

"We have the opportunity to send President Obama back to Chicago — or Kenya," Jason Thompson, the son of former Wisconsin Gov. Tommy Thompson said at a brunch on Sunday. Republican National Committee Chairman Reince Priebus also attended the brunch, according to the Republican Party Of Kenosha County's website.

Video of the event was first published online on Sunday by BuzzFeed.

"We're taking donations for that Kenya trip," one woman can be heard saying in the video.

When asked about the remarks, the Republican candidate reportedly insisted: "I haven't seen a video... I don't know what you're talking about."

A spokesperson for Thompson's campaign later told BuzzFeed that his son had offered an apology.

"The Governor has addressed this with his son, just like any father would do," the spokesperson explained in an email. "Jason Thompson said something he should not have, and he apologizes."

At a second fundraiser on Sunday, Republican vice presidential nominee Paul Ryan called Thompson his "greatest mentor."

"Scott [Walker], Reince and I are protégés of the Tommy Thompson farm team,” Ryan said. "He is a great leader who has done extraordinary things."

The latest Real Clear Politics average of polls showed Democratic candidate Tammy Baldwin holding a 3 point lead over the former Republican governor.

Watch this video, uploaded Oct. 14, 2012.