Nigel Farage has been accused of giving "legitimisation to racism" by the Archbishop of Canterbury.
The Most Rev Justin Welby said Mr Farage was "accentuating fear for political gain", which he said was "absolutely inexcusable".
Giving evidence to the Commons Home Affairs Committee, he was responding to comments by the Ukip leader that remaining in the EU could lead to sex attacks such as those seen in Cologne on New Year's Eve.
The archbishop said such comments had themselves resulted in violence in the past.
Asked about the remarks by Labour MP Keith Vaz, chair of the committee, the archbishop said he agreed they were racist.
"I think that is an inexcusable pandering to people's worries and prejudices," he said.
"That is giving legitimisation to racism, which I've seen in parishes in which I've served, and has led to attacks on people in those parishes. We cannot legitimise that.
"What that is, is accentuating fear for political gain and that is absolutely inexcusable."
He added that he condemned the comments "without hesitation".
Mr Farage drew widespread condemnation with his claim at the weekend that the threat to British women of mass sex attacks - such as occurred in Cologne - if Britain voted to stay in the EU was the "nuclear bomb" of the referendum campaign.
Mr Farage will take questions from an audience in a live EU referendum programme on ITV at 9pm, as will Prime Minister David Cameron.