JERUSALEM – With a few words in a largely conciliatory speech to the United Nations, Iran’s new president took aim at an Israeli fear: that international pressure on Tehran’s nuclear program could lead to scrutiny of Israel’s own secretive nuclear facilities.

Israel is widely believed to possess dozens of atomic weapons under a program dating back more than half a century. But in a major pillar of its national defense strategy, it neither confirms nor denies possessing these arms — a policy known as “nuclear ambiguity,” meant to keep its enemies off balance.

Iran will likely try to draw attention to the Israeli policy as it prepares to engage the West in a new round of nuclear talks. While Israel does not appear to face any immediate threat of global censure, the issue nonetheless could be embarrassing given its repeated calls for the world to crack down on what it says is an Iranian campaign to develop a nuclear bomb.

Iran, which denies the accusations, has long claimed to be the victim of a “double standard” when compared to Israel — yet it is a double standard the world appears to largely have accepted.

In his address to the U.N. General Assembly on Tuesday, Iranian President Hasan Rouhani appeared to be referring to Israel when he told the world body that he is ready to resolve the nuclear standoff with the West.

“Iran’s nuclear program — and for that matter, that of all other countries — must pursue exclusively peaceful purposes,” he said. He did not mention Israel directly.

Yet in the same session, Rouhani called the Holocaust “a massacre of the Jews by the Nazis,” in contrast to past Iranian statements that cast doubt on the historical event that led to the establishment of Israel as a Jewish state. Iran officially considers Israel illegitimate.

Although Rouhani said Iran completely condemns the Holocaust, he said it is important that victims “not seek compensation by victimizing other groups.” That was a reference to Palestinians displaced by Israel’s founding and to Israel’s occupation of West Bank land that the Palestinians seek for an independent state.

Rouhani would not address what he called the “scale and numbers” of the Holocaust. “Why don’t we just leave that to the experts?” he said.

Israel, along with many Western countries, believes that Iran is developing a nuclear weapon — or at least is aiming to achieve a “threshold,” able to quickly assemble a bomb. Israel says a nuclear-armed Iran would pose a grave danger, citing Iranian calls for the Jewish state’s destruction, its development of long-range missiles and support for hostile Arab militant groups.

Israeli Prime Minister Benjamin Netanyahu dismissed Rouhani’s outreach to the West as a ploy to ease international sanctions and gain more time to build the bomb. Netanyahu has urged the international community to increase, not ease, the pressure, and to maintain a “credible” military threat until Iran dismantles its nuclear program.

Israeli officials reject Iranian attempts to make Israel part of the debate, calling it a cheap diversionary tactic. Asked about this possible linkage, Netanyahu’s spokesman, Mark Regev, would only say that Tehran would be judged not by words, but by its actions.

Israel launched its nuclear program around the time of independence in 1948, a time when neighboring Arab countries declared war against the fledgling Jewish state, and it has been an undeclared nuclear power since the mid-1960s, said Shlomo Aronson, an expert on Israel’s nuclear program at the Hebrew University. The program is believed to be headquartered at a heavily fortified facility in the southern desert town of Dimona.

The international community has quietly tolerated this arrangement out of an understanding of Israel’s unique security needs, he said.

“There is an international acceptance that Israel has no choice but to depend on its nuclear power without talking about it,” said Aronson. “In today’s power relations, where there are 6 million Jews against 400 million Arabs . . . Israel has no choice but to be an undeclared nuclear power.”

He said many Middle Eastern countries remain committed to Israel’s destruction. “What is stopping them from doing it? Dimona,” he said.

Israel says only that it will not be the first country to introduce nuclear weapons into the Middle East. But there is strong evidence that it has a large and sophisticated atomic arsenal.

In 1986, Mordechai Vanunu, a disgruntled technician at the Dimona facility, handed photos of the facility to a British newspaper. They led foreign experts to conclude that Israel had the world’s sixth-largest nuclear stockpile. Israeli intelligence agents later seized Vanunu in Rome, and he spent 18 years in prison.

In an apparent slip of the tongue, then-Prime Minister Ehud Olmert appeared to acknowledge that Israel has nuclear weapons in a 2006 interview with a German TV station. Shimon Peres also seemed to admit to having nuclear arms in calling for a nuclear-free Middle East in 1995, when he was Israel’s prime minister.

“Give me peace, we will give up the nuclear capability. That’s the whole story,” Peres said at the time. He is believed to have played a key role in developing the country’s nuclear program in the 1950s and ’60s.

Analysts Hans M. Kristensen and Robert S. Norris said in an article published earlier this month that Israel has 80 nuclear warheads.

Israel is among four countries believed to possess nuclear weapons that have not joined the Nuclear Non-Proliferation Treaty (NPT), a landmark 1970 agreement that attempts to stop the spread of nuclear arms. The others are India, Pakistan and North Korea, countries that have all declared their nuclear capabilities.

For decades, the Israeli strategy of ambiguity has largely worked. Last week, Israel and its allies fended off an Arab-led attempt to censure its refusal to acknowledge that it possesses nuclear weapons and put them under international oversight. But if international engagement with Iran gains traction, calls for Israel to be held accountable could grow.

While Tehran recognizes it is unlikely to make much headway with the West, its strategy is aimed at a more global audience.

It has used its prominent position in the Nonaligned Movement, a grouping of more than 100 developing countries, to bash Israel over its presumed nuclear arsenal. Rouhani told a summit of Asian leaders this month that Iran is committed to the NPT while noting Israel’s refusal to join.

But there is probably also a visceral pleasure for Iran to land political punches that could unsettle Israel. Tehran led the call for a proposed international conference in Finland last year to declare the Middle East a “nuclear weapons-free zone.”

The U.S. helped scuttle the plans, apparently to save Israel embarrassment. But in response to the cancelation, the U.N. General Assembly approved resolution 174-6, with six abstentions, calling on Israel to quickly open its nuclear program for inspection and join the NPT “without further delay.” Resolutions by the General Assembly are not legally binding, but they reflect world opinion and can carry political weight.

Ephraim Asculai, a former official of the Israel Atomic Energy Commission, said Israel’s precondition to discussing its nuclear program is peace in the region. “As long as there is no peace with our enemies, why should Israel make a step forward on that?” he asked.