Cotton, Iranian leader tangle again on social media

Iranian Foreign Minister fires back at Sen. Tom Cotton
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    Iranian Foreign Minister fires back at Sen. Tom Cotton

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Iranian Foreign Minister fires back at Sen. Tom Cotton 00:31

(CNN)Sen. Tom Cotton threw down the gauntlet Wednesday, taking aim at one of his favorite Twitter nemeses -- Iranian Foreign Minister Mohammad Javad Zarif.

The latest blows in their very public battle came after Zarif make a joke at Cotton's expense while speaking to a crowd at New York University.
Asked how soon Iran expects sanctions relief under a nuclear agreement with the U.S. and it's allies, Zarif wrapped his answer with a swipe at the freshman senator, prompting laughter from the audience, and from moderator David Ignatius of The Washington Post.