A new campaign video for a Republican congressional candidate implies that German gun controls contributed to deaths during the Holocaust because people didn't have firearms to defend themselves.
The comments quickly drew strong rebukes from Democrats and Jewish organisations.
In the video, Samuel Wurzelbacher loads a shotgun and fires at pieces of fruit placed on wooden posts.
"In 1939, Germany established gun control," he says. "From 1939 to 1945, six million Jews and seven million others, unable to defend themselves, were exterminated."
He ends the video by saying: "I love America."
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Gun control opponents have long held that Adolf Hitler was able to seize power in Germany in part because of controls on firearms.
"Using the memories of the six million Jews killed in the Holocaust to make a political point is never appropriate, under any circumstances," said David Harris, president of the National Jewish Democratic Council.
Ohio Democratic Party chairman Chris Redfern called the video "incredibly offensive".
Wurzelbacher, who became known as "Joe the Plumber" during the 2008 presidential campaign after questioning Barack Obama at an event, is running as a Republican in Ohio's 9th US House district.
Wurzelbacher defended his statements on Twitter, posting that he did not say that gun control caused genocide.
