Story highlights "I don't know about the Hitler comparison," Donald Trump said Tuesday

Comedian Louis C.K. on Trump: "It was funny for a little while. But the guy is Hitler."

(CNN) Donald Trump on Tuesday addressed criticism of a new practice at his rallies that has been compared to the "Heil" salute from Nazi Germany, dismissing the controversy as "ridiculous" before saying he would look into ending it.

"I don't know about the Hitler comparison. I hadn't heard that, but it's a terrible comparison. I'm not happy about that certainly," Trump said on ABC's "Good Morning America."

Recently, Trump has started asking voters to raise their right hand and pledge to support him -- creating an image that some have argued evokes the rise of Adolf Hitler, particularly when coupled with his sharp rhetoric toward minority groups like Mexicans and Muslims.

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Hitler comparisons are not new for Trump. Comedian Louis C.K ., in a postscript to a Saturday email about the latest episode of his web series "Horace and Pete," he asked fans and readers to "please stop it with voting for Trump."

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