Tel Aviv — In a sketch from a recent episode of the Israeli television satire “Wonderful Country,” a real-estate broker showing a property to a young couple boasts of a sea view but opens up the window to reveal a building façade.

“Ah, in June, none of this building row will be here,” the broker explains. “There’s that thing with Iran this summer. So everything works out, the bomb!”

The comedy sketch highlights the nagging but quiet jitters here about creeping progress in Iran’s nuclear program and about the possibility of a regional war with hundreds of missiles on Israeli cities in the event of an Israeli attack.

Amid worrying reports last week of continued Iranian uranium enrichment and installation of underground centrifuges, Israeli Prime Minister Benjamin Netanyahu seemed to get backing for his contention that U.S.-led international sanctions and diplomatic talks are ineffective so far.

“I don’t see anything progressing — [America] declares sanctions, and [Iran] doesn’t give a damn,” said Gili Belostotsky, a 19-year-old barista at a café in central Tel Aviv. “I don’t doubt the U.S. isn’t trying or not making an effort, but how much is that changing anything?”

After several rounds of inconclusive talks and stepped-up economic sanctions, the International Atomic Energy Agency is expected to say in a forthcoming report that Iran has nonetheless added hundreds of centrifuges at the underground enrichment site that will produce uranium that could be used in an explosive.

Though the Iranians haven’t yet begun work on assembling a weapon and the new information doesn’t indicate any significant acceleration in the pace of their nuclear program, analysts say that it does highlight an ongoing complaint of Israel’s leadership: that the Obama administration needs to make a more credible threat that it will use military force if necessary.

“The Iranians think the U.S. isn’t serious,” said Yossi Melman, an intelligence commentator for the liberal Haaretz newspaper and the co-author of “Spies Against Armageddon.”

“If the leadership would realize that America means business and that it’s a matter of months in which they would be bombed, then they would change their behavior,” he said.

Melman said he doesn’t expect the atomic agency reports will reveal anything new, but continued progress of Iran strengthens the argument of Netanyahu, who said last month alongside Republican presidential candidate Mitt Romney that sanctions and diplomacy had not slowed Iran “one iota.”

Israeli leaders like Defense Minister Ehud Barak have strongly hinted that only an attack against Iran — preferably by the U.S. — will prevent Iran from obtaining nuclear weapons.

But analysts believe that Iran can be intimidated into backing down. They say that Iran halted progress on its nuclear program after the U.S. invasion of Iraq in 2003, when Tehran though it might be next. Iran also backed down from a threat to close oil-supply shipping in Straits of Hormuz because the U.S. and its allies delivered a clear and resolute message that it would not accept such a move.

“In the same way that Obama knew how to be firm and clear about the closing of Hormuz, he needs to communicate that same determination in the same fashion” about the nuclear program, said Emily Landau, a fellow at Tel Aviv University’s Institute for National Security Studies. “It’s time to get serious.”

The new information about Iran’s nuclear progress comes as Iran hosted this week a conference of “non-aligned” countries with United Nations Secretary General Ban Ki Moon in attendance — a move that the U.S. and Israel sought to prevent.

However, Landau said the conference serves mainly as a public relations vehicle for the regime and will be forgotten within weeks. Observers shouldn’t be fooled that Iran is breaking out of its isolation.

“The isolation of Iran is happening on a daily basis, through economic sanctions,” she said.

In lieu of more strident threats of force by the U.S., Israeli leaders like Barak and Netanyahu have been threatening for months that Jerusalem will act alone if necessary. Analysts say that the Israeli policy of saber rattling has prodded the international community to step up a drive for sanctions.

But that saber rattling has kicked up more anxiety in Israel about war and a debate over the wisdom of a preemptive attack. In recent weeks President Shimon Peres has advised against a lone strike, and even Chief of Staff Benny Gantz is reported to be opposed to such a move. Polls suggest that Israelis don’t want to attack Iran without the backing of a superpower.

“The great failure of Netanyahu and Barak’s strategy has been to lose the majority of the Israeli public on this issue,” said Yossi Klein Halevi, a fellow at the Shalom Hartman institute. “What’s happened is that rather than debate the consequences of a nuclear Iran, the public is now debating the consequences of an Israeli strike. Netanyahu and Barak need urgently to reframe the domestic debate.’’

Last week, the Channel 2 television weekend news magazine aired a lengthy report suggesting that Israel’s “home front” is not sufficiently prepared for war. The news magazine said that there is a shortfall of millions of gas masks and that cities like Tel Aviv and Haifa lack sufficient public shelters.

While opposition politicians have predicted that the reported lack of preparedness is liable to create a state of domestic unrest, a former Israeli air force chief, Eitan Ben Eliyahu, was quoted by the conservative newspaper Makor Rishon predicting that Israelis will rise to the challenge.

“The people are willing to sacrifice for this,” Ben-Eliyahu said. “When the public is certain that everything is being done properly, there will be discipline, people will be in place and the number of casualties won’t be high.”

Indeed, even with the steady stream of war chatter, there are little outward signs of anxiety in Tel Aviv. There has been no crush of Israelis demanding gas masks. Klein Halevi said this owes to Israelis’ tendency to cope with threats by living in the present.

But Melman said that bystanders and acquaintances approach him, inquiring about the possibility of war.

“People ask me, ‘Tell us, when we should leave Israel.’ Or, ‘When we should go to the shelters?’ It’s the talk of the town.”

Back on the streets of central Tel Aviv, a grocer and a salesman joked about getting military call-ups in case of an emergency. Moshe Parnas, a 34-year-old salesman likened the prolonged state of uncertainty to a pressure cooker.

“You know how you make cholent? You put it on burner for hours on a low flame. The U.S. has put us on the oven. And ultimately we’ll explode.”