UN atomic watchdog chief Mohamed ElBaradei warned that any attack on Iran would transform the region into a “ball of fire,” in an interview with Al-Arabiya television broadcast on Saturday.
His comments come after US media reported that Israeli jet pilots trained for a possible strike on Iranian nuclear sites.
“A military strike (against Iran) would in my opinion be worse than anything else... It would transform the Middle East region into a ball of fire,” said ElBaradei, director general of the International Atomic Energy Agency (IAEA).
Should a strike be carried out, he told the Dubai-based channel, he would find it impossible to continue as head of the IAEA.
An attack, he added, would do nothing but harden Iran's position in its row with the West over its nuclear programme.
“A military strike would spark the launch of an emergency programme to make atomic weapons, with the support of all Iranians, including those living abroad,” ElBaradei said.
He did not believe, he added, that there was any “imminent risk” of proliferation given the current status of Iran's nuclear programme and made it clear he would “not have a place” as head of the IAEA in the event of a military strike against Iran.
The New York Times on Friday cited US officials as saying a major military exercise carried out by Israel earlier this month seemed to be a test-run for any potential strike against Iran's nuclear facilities.
In Athens, an official with the Greek air force's central command confirmed to AFP the substance of the report, stating that it had taken part in “joint training exercises” with Israel off the Mediterranean island of Crete.
The manoeuvres, code-named “Glorious Spartan 08,” took place on May 28 and June 12, and consisted of aerial exercises and knowledge exchange, said the Greek source, who requested anonymity.
The goal was for more than 100 Israeli F-16 and F-15 fighter jets to prepare for long-range strikes and demonstrate Israel's serious concern over Iran's nuclear ambitions, the Times reported.
On June 6, an Israeli Deputy Prime Minister, Shaul Mofaz, warned that Iran would face attack if it pursues what he said was its nuclear weapons programme.
In Tehran, senior cleric Ayatollah Ahmad Khatami warned Israel of a "strong blow" if it attacks Iran. "If enemies, especially Israelis and their supporters in the United States, would want to use a language of force, they should rest assured that they will receive a strong blow in the mouth," Khatami said.