UNITED NATIONS -- Heading into a historic meeting on Tehran's disputed nuclear activities, Iran's new president called on Israel on Thursday to join an international treaty banning the spread of nuclear weapons, chiding the Jewish state for being the only Mideast nation that has failed to do so.
President Hassan Rouhani addressed a United Nations forum on nuclear disarmament, speaking as chair of an organization of mostly developing countries that has long demanded that Israel sign the landmark 1979 Non-Proliferation Treaty.
His comments came hours before a meeting of world powers on Iran that aims to pave the way for the first round of substantive negotiations on Tehran's nuclear program since April.
The Thursday afternoon meeting, on the sidelines of the annual U.N. General Assembly, will mark the highest-level direct contact between the United States and Iran in six years as Secretary of State John Kerry comes face-to-face with Iranian Foreign Minister Javad Zarif.
The talks also will test the Islamic Republic's apparent willingness to reach a deal to resolve international concerns over its nuclear program, after years of defiance.
Iran insists its nuclear program is for peaceful purposes only, and says it needs to enrich uranium to produce reactor fuel and for medical purposes. But world powers fear Iran is enriching uranium to build warheads, and have imposed strict economic sanctions to punish Tehran to failing to halt its nuclear program.
Rouhani, speaking Thursday morning for the Nonaligned Movement, said all nations should be subject to International Atomic Energy Agency inspections and other nuclear safeguards. Increased transparency, including more inspections, is a key part of the negotiations over Iran's nuclear program.
"No nation should possess nuclear weapons, since there are no right hands for these wrong weapons," he said.
He added: "Almost four decades of international efforts to establish a nuclear weapon-free zone in the Middle East have regrettably failed." He noted that Israel is the only state in the region that has not embraced the Non-Proliferation Treaty.
A spokeswoman for the Israeli mission at the U.N. did not have an immediate comment, as the mission was closed for an official holiday.
Since his June election, Rouhani has made clear he is seeking relief from the international sanctions and has welcomed a new start in nuclear negotiations in hopes they could ease the economic pressure. He has said he has the full support of Iranian Supreme Leader Ayatollah Ali Khamenei, who has the final word on all important matters of state, including the nuclear question.
Encouraged by signs that Rouhani will adopt a more moderate stance than his hard-line predecessor, Mahmoud Ahmadinejad, but skeptical that the country's supreme leader will allow a change in course, President Barack Obama has directed Secretary of State John Kerry to lead a new outreach to explore possibilities for resolving the long-standing dispute.
However, Obama and other U.S. officials have said Iran must prove its commitment with actions, not just words.
Zarif, who will represent Iran in Thursday's meeting, has urged step-by-step compromises between his country and world powers to advance the negotiations. The United States, Britain, France, Russia, China and Germany will participate in the meeting, with European Union foreign policy chief Catherine Ashton leading the talks.
Kerry on Thursday predicted it would be a "good meeting." Asked what he would need to hear from the Iranians to show that they're serious, he said: "I'll let you know after they've been serious."
In his speech to world leaders at the U.N. on Tuesday, Rouhani repeated Iran's long-standing demand that any nuclear agreement must recognize its right under international treaties to continue enriching uranium. The U.S. and its allies have long demanded a halt to enrichment, fearing Tehran could secretly build nuclear warheads.
Rouhani also insisted that any deal be contingent on all other nations declaring their nuclear programs, too, are solely for peaceful purposes -- alluding to the U.S. and Israel.
Iran watchers say Rouhani may have limited time to reach a settlement -- possibly a year or less -- before Khamenei decides negotiations are fruitless. That may explain Zarif's call to reach a deal in a short time span.
Rouhani has come across as a more moderate face of the hard-line clerical regime in Tehran. He appears to be trying to tone down the caustic rhetoric of his predecessor, Mahmoud Ahmadinejad, with regard to Israel -- one of the points of friction in relations with the West.
Still, his speech to the U.N. was peppered with Iran's traditional digs at America and the West -- a reminder that a diplomatic warming will not come quickly or easily.
Follow Lara Jakes on Twitter at: https://twitter.com/larajakesAP