Video of Israel and Iran Sparring at U.N.

Following an extended attack on the credibility of Iran’s new president by Israel’s prime minister in an address to the United Nations on Tuesday, an Iranian diplomat exercised his country’s right to reply with scathing remarks of his own, as my colleagues Somini Sengupta and Rick Gladstone report.

In his remarks, Prime Minister Benjamin Netanyahu dismissed recent diplomatic overtures by President Hassan Rouhani as a disingenuous “charm offensive.”

Citing a passage from a book Mr. Rouhani wrote about his work as a negotiator over Iran’s atomic energy program, Mr. Netanyahu asserted that the new president’s real goal was to engage in talks just to buy time for technical advances that would make the production of a nuclear weapon possible.

Israel’s prime minister, who has tried to employ humor as a rhetorical device in previous speeches accusing Iran of deceit over its nuclear ambitions, even mentioned the uranium ore known as yellowcake in a pun. “You see,” Mr. Netanyahu said, “Rouhani thinks he can have his yellowcake and eat it too.”

Speaking after Mr. Netanyahu, a deputy ambassador at Iran’s Mission to the United Nations, Khodadad Seifi, defended his nation’s “inalienable right to peaceful nuclear energy” and called the Israeli prime minister’s remarks “extremely inflammatory.”

In his response, the Iranian diplomat suggested that the Israeli prime minister’s position on weapons of mass destruction was hypocritical as the leader of a nation thought to possess a stockpile of its own nuclear arms. Mr. Netanyahu “talked a lot about W.M.D.s in the Middle East,” Mr. Seifi said, “without mentioning that Israel is the only one in the region that possesses all types of W.M.D.s but is not party to any of the treaties banning them.”

The diplomat concluded by citing a recent reply to Israeli criticism from Iran’s new foreign minister, Mohammad Javad Zarif. “We have been accused of having a smile attack,” Mr. Seifi said. But, he added, “a smile attack is better than a military attack. And indeed a smile policy is much better than lying.”

Later in the day, Iran’s diplomatic outreach via social networking continued in an exchange of messages between a founder of Twitter, Jack Dorsey, and @HassanRouhani, an English-language account in the name of Iran’s president apparently run by his aides. Asked about Internet freedom in Iran, which remains severely limited, the president’s Twitter persona insisted that he was working to ensure that Iranians would be able ton exercise “their right” to “accessall info globally.”

Evening, @Jack. As I told @camanpour, my efforts geared 2 ensure my ppl'll comfortably b able 2 access all info globally as is their #right.

â€" Hassan Rouhani (@HassanRouhani) October 1, 2013