McCain compares Iran's Ahmadinejad to monkey in tweet (VIDEO)

US Sen. John McCain at the 48th Munich Security Conference in Munich, Germany, on Feb. 2, 2012.

Sen. John McCain is in hot water after comparing Iranian President Mahmoud Ahmadinejad to a monkey in a tweet.

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On Monday, the Republican and former-presidential candidate sent out this tweet:

When he got some criticism for what he thought was an innocent joke, he tweeted back to followers:

But that response didn't seem to appease fellow Republican Justin Amash of Michigan, who fired back:

As the Twitter battle ensued, a third conservative joined the discussion. John Podhoretz tweeted a slew of responses to McCain's initial joke, including these:

This isn't the first time McCain has put his foot in his mouth when it comes to Iran. According to NBC News, in 2007, the 76-year-old veteran cracked a joke about the country by changing the words to the Beach Boys' song "Barbara Ann" to "Bomb Iran."