Confusing the Arabic honorific with the term Sikh, Romney mispronounced it and was found talking about 'sheik' people.
Earlier in the day, the Republican spoke correctly of the Sikh religion when he observed a moment of silence at a campaign event in Illinois. But the slip of tongue came at the West Des Moines fundraiser in Iowa.
"We had a moment of silence in honour of the people who lost their lives at that sheik temple. I noted that it was a tragedy for many, many reasons," he said referring to his discourse in Chicago.
He went on: "Among them are the fact that people, the sheik people, are among the most peaceable and loving individuals you can imagine, as is their faith".
Romney's spokesman, Rick Gorka, when asked about the comments, insisted that the mix-up was a mispronunciation.
"He misspoke," Gorka said.
"He mispronounced similar sounding words. He was clearly referring to the tragedy in Wisconsin," he was quoted as saying in a Huffington Post report.
The paper said: 'The Republican presidential hopeful used the Arabic term, which typically refers to an elder or religious leader, to discuss Sikhism, a religion that originated in the Punjab region of South Asia'.
Romney, who is being supported by two top Indian American politicians -- Nikki Haley and Bobby Jindal -- observed a moment's silence at an Illinois event in honour of the people who lost their lives in Wisconsin.
"The tragedy is even more profound because the Sikh religion and the Sikh people are such peaceable, loving individuals," Romney said correctly at this campaign event.
"I think it's also more tragic because the shooter was apparently someone who was motivated by hate, hate based on race, hate based on religion. For all those reasons, this is something which touches us very deeply," said the Republican presidential candidate.