Israeli Prime Minister Benjamin Netanyahu played the spoiler to Iran's attempts to ease relations with the West, calling the Iranian leader "a wolf in sheep's clothing" and declaring that Israel will do whatever it takes to prevent Tehran from developing nuclear weapons, even if it has to stand alone.
Speaking to world leaders at the UN General Assembly on Tuesday, Netanyahu gave a point-by-point rebuttal of President Hassan Rowhani's speech last week signalling a willingness to discuss Iran's disputed nuclear programme.
Accusing Rowhani of a "charm offensive" aimed at getting the West to lift crippling sanctions, Netanyahu portrayed him as "a loyal servant of the regime" who has done nothing to stop his country's nuclear programme since he took office in June.
Rowhani, he added, must have known about terrorist attacks carried out by Iranian agents in Argentina, Saudi Arabia and Berlin in the 1990s because he was national security adviser at the time.
Israel's hope for the future is challenged "by a nuclear-armed Iran that seeks our destruction", the Israeli leader said.
A year ago at the General Assembly, Netanyahu held up a drawing of a spherical bomb with a sputtering fuse, then pulled out a red marker and drew a line across what he said was the threshold Iran was fast approaching and which Israel would not tolerate - 90 per cent of the uranium enrichment needed to make an atomic bomb.
"Iran has been very careful not to cross that line," Netanyahu said on Tuesday.
"I wish I could believe Rowhani, but I don't because facts are stubborn things, and the facts are that Iran's savage record flatly contradicts Rowhani's soothing rhetoric."
He pointed to Iran's continuing enrichment of uranium to a 20 per cent level, its addition of thousands of new centrifuges and its development of intercontinental ballistic missiles "whose sole purpose is to deliver nuclear warheads" that the United States says will be capable of reaching New York in three or four years.
"Israel will never acquiesce to nuclear arms in the hands of a rogue regime that repeatedly promises to wipe us off the map," Netanyahu declared. "I want there to be no confusion on this point: Israel will not allow Iran to get nuclear weapons. If Israel is forced to stand alone, Israel will stand alone."
After his address, Netanyahu, like Rowhani, received warm applause but Iran's seat in the assembly chamber was empty, as it continued its long-standing boycott of Israeli speeches.
Iran responded later with Khodadad Seifi, a deputy ambassador to Iran's UN mission, accusing Netanyahu of "sabre rattling" and warning that he should "avoid miscalculation".
"Iran's centuries-old policy of non-aggression must not be interpreted as its inability to defend itself," Seifi said. "The Israeli prime minister had better not even think about attacking Iran, let alone planning for that."