Defense Minister Ehud Barak restated Israel's fears of a nuclear-armed Iran on Thursday, after Israel's top general appeared to clash with the government's line by describing the Islamic republic as "very rational" and unlikely to build a bomb.

Gantz's stance on Iran's intentions appeared to put him at odds with Israel's political leaders, who have staked out a more hardline position. Gantz denied that was the case Thursday, saying there was no internal disagreement over Iran's aims.

Addressing foreign diplomats on Israel's Independence Day, Barak said Iranian leaders were not "rational in the Western sense of the word, which implies the quest for status quo and the peaceful resolution of problems."

It would border on "blindness or irresponsibility" to believe otherwise, Barak said. He said Iran, with its religiously fuelled calls for the Jewish state's demise, was seeking regional hegemony and was "undeterred by the apocalyptic."

While Barak's speech reiterated international concerns that Iran's uranium enrichment program has military designs and Israel's readiness to attack its foe pre-emptively, some of the language was unusually strong for Barak. A transcript circulated to the media had key passages underlined.

Another official told Reuters that Barak wanted to "set things straight" after Israel Defense Forces Chief of General Staff Lt. Gen. Benny Gantz said in a newspaper interview this week that Iran was preparing components of a bomb but was unlikely to "go the extra mile" of assembling it, given the likely global backlash. Barak's speech did not mention Gantz specifically.

"I think the Iranian leadership is composed of very rational people," Gantz told Haaretz, the liberal daily, on Wednesday.

In lobbying world powers to stiffen sanctions designed to curb Iran's uranium enrichment, Israel has long appealed to their worries about Middle East destabilization and oil shock.

This has entailed warning that an Iranian bomb would embolden Islamist militants, spark arms races, and rattle energy markets. It has also entailed hinting that Israel -- assumed to have the region's only atomic arsenal -- could go to war to thwart what it regards as a mortal threat should it deem that foreign diplomacy with Tehran is at a dead end.

Six world powers revived negotiations with Iran in Istanbul last month and are due to resume them in Baghdad on May 23.

Barak was pessimistic about the talks, saying Iran was buying time to dig in behind defenses that would allow its nuclear facilities to fend off aerial attack.

"The sanctions today are harsher that in the past," he said. "But the truth must be told. The chance that, at this level of pressure, Iran will meet the international demand to stop the program irrevocably -- that chance appears to be low."

During Israel's Holocaust Remembrance Day last week, Prime Minister Benjamin Netanyahu said Iran was "feverishly working to develop atomic weapons" to use against his country. Speaking on CNN on Tuesday, Netanyahu said he would not want to bet "the security of the world on Iran's rational behavior." A "militant Islamic regime," he said, "can put their ideology before their survival."

The portrayal of Iran as irrational -- willing to attack Israel with a nuclear weapon even if it means inviting catastrophic retaliation in kind -- could bolster a case for pre-emptive bombing to take out its atomic facilities.

The U.S. has also not ruled out military action as a last resort. But many allies of Washington, and even some senior U.S. officials, fear such an attack could ignite a broader war while only delaying Iran's nuclear advances.

Gantz's assessment appeared to be in step with the view of his U.S. counterpart, Gen. Martin Dempsey, who said in a CNN interview in February that he believed Iran was a "rational actor" and it would be premature to take military action against it.

"Iran with nuclear military capability will start an arms race in the Middle East. Saudi Arabia, Turkey, and even the new Egypt will be forced to join the race," Barak said Thursday at a conference at the Air Force Center in Herzliya.

"A nuclear Iran will work to support Hezbollah and Hamas, and will sow terror throughout the world," Barak warned.

On the U.S.’s approach, Barak said, "The U.S. government understands very well that Israel has a different take on the issue and the risks involved for Israel. The government understands that Israel must be able to defend itself on its own."

One day after his interview with Haaretz, Gantz also addressed Israel's willingness to defend itself, telling The Associated Press on Thursday, "The military force is ready. Not only our forces, but other forces as well. We all hope that there will be no necessity to use this force, but we are absolutely sure of its existence."

Gantz did not mention which countries would be willing to intervene directly in Iran, but his statement underlined the support Israel is receiving for a possible military operation against the Islamic Republic. Gantz emphasized that he is not speaking in the name of any other country.

President Shimon Peres echoed Gantz's comments. In an interview Thursday with Israeli Channel 2 TV, Peres said, "We are not alone on this issue."

The president dismissed claims that Israel faces an existential threat. "We have overcome, I believe, more difficult situations," he said.

According to French news agency AFP, U.S. Secretary of Defense Leon Panetta said on Thursday that he hoped Gantz's assessment of Iran's “rational” leadership was correct.

"I would hope [Gantz is] correct and he knows something more than I do," Panetta said during a visit to Chile, according to AFP. "I do not have any specific information that indicates [the Iranians] have made any decision one way or another on whether to build a nuclear weapon. I would like to hope that because of the leadership of the United States, the international community and the leadership of Israel, they can make the right decision."