Israel's tough talk of military action against Iran's nuclear program has unleashed a strong backlash at home, with a growing number of voices urging the government not to attack without the support of the United States.

Israeli leaders, who have long issued veiled threats against Iran, now appear to be preparing the country for war. New gas mask distribution centers have opened, a nationwide missile alert system has been tested and an official this week warned of hundreds of casualties if Israel unilaterally strikes Iran.

The heightened rhetoric has fueled jitters that the zero hour is near. But there are also growing signs of discontent with the government's approach, with critics accusing Prime Minister Benjamin Netanyahu and his defense minister, Ehud Barak, of recklessly plunging Israel into an unprecedented missile war.

"I'm very afraid. I want peace, not war. I absolutely don't want Israel to strike Iran," said Pnina Grinbaum, a 55-year-old government clerk in Jerusalem.

Opinion polls have shown that while Israelis agree a nuclear-armed Iran would pose a grave threat, most think Israel should not act alone but coordinate any military option with Washington .

Israel's figurehead president, Shimon Peres, appeared to take a swipe at Barak and Netanyahu on Thursday when he told a popular news program that Israel must trust President Barak Obama's pledges to prevent Iran from getting a bomb.

"It is clear to us now that we cannot do this alone," Peres said. "It is clear to us that we need to work together with America."

Israel, like most of the West, is convinced Iran is lying when it says its nuclear program is designed to produce energy, not bombs. It has broadly suggested it would be prepared to use military force — as it did in 1981 and 2007, when it attacked unfinished nuclear reactors in Iraq and Syria — to keep Iran from becoming a nuclear power.

Israel says a nuclear-armed Iran would pose a mortal threat, given Iranian calls for Israel's destruction and its support for anti-Israel militant groups in Lebanon and Gaza.

Israeli leaders have also warned that the time to act is growing short, perhaps no later than autumn. The failure of economic sanctions and a U.S.-led international dialogue to make headway with Iran has compounded fears that Iran is moving ever closer to weapons capability.

"We are getting close to crunch time," an Israeli government official said Thursday, speaking on condition of anonymity because he was not allowed to discuss policy toward Iran.

The latest war fears escalated last weekend following a lengthy newspaper interview with an unidentified senior Israeli official who warned that Israel has never before faced such a threat to its survival.

"If we do not act, it's almost certain that Iran will go nuclear," the official — widely assumed to be Barak — told the Haaretz newspaper. "If we do act, there's a good chance that Iran will not go nuclear for a long while."

Further fueling public unease, the military on Sunday tested a new early-warning system by sending out hundreds of thousands of text messages to cellphone users advising them of an incoming missile attack. New gas mask distribution centers opened this week. Contractors are fortifying hospitals and schools and building shelters.

Also this week, Israel's chief civil defense official said the government estimated an attack on Iran would trigger a monthlong war, fought on multiple fronts, with Tehran and its proxies in Lebanon and Gaza — and hundreds of Israeli casualties.

"I'm very nervous about the Iranian threat and it's kind of creepy that I'm getting a gas mask right now," 25-year-old Cheryl Lieberman, a recent immigrant from New York, said Thursday as she stood in line for a mask at a Jerusalem mall.

A new poll issued Thursday said 61 percent of Israelis believe Iran should not be attacked without U.S. consent. The Dahaf Institute poll of 516 people had a margin of error of 4.5 percentage points. Other surveys have shown similar reluctance to have Israel act alone.

Opposition leader Shaul Mofaz, a former military chief, accused Netanyahu of "generating panic" by "rashly" leading an ill-prepared home front into conflict.

The Israelis are "scared of your lack of judgment, scared that you are being led and are not leading, scared that you are putting a dangerous and irresponsible policy into motion," he said in parliament, addressing Netanyahu.

Apart from risking a broad regional conflict and soaring global oil prices, an assault against Washington's wishes would create a rift with Israel's strongest ally, and possibly even draw the U.S. military into the conflict.

Washington has vowed to take military action if necessary to block Iran from going nuclear but has warned Israel against acting prematurely, insisting sanctions and diplomacy should be given more time to work.

Israeli leaders say the U.S., with an unparalleled arsenal of combat planes and bunker-busting bombs, can wait longer to act. That rhetoric suggests they are not convinced by American calls for restraint from a stream of high-level U.S. visitors — or reassured by U.S. vows to keep Iran from going nuclear.


Blake Sobczak and Ian Deitch in Jerusalem contributed to this report.