Iran's new president has called on Israel to join an international treaty banning the spread of nuclear weapons, chiding the Jewish state for being the only Middle East nation that has failed to do so.
The speech by president Hassan Rouhani came hours before a meeting that will mark the highest-level direct contact in six years between the United States and Iran over Tehran's disputed nuclear activities.
"Almost four decades of international efforts to establish a nuclear weapon-free zone in the Middle East have regrettably failed," Mr Rouhani told a United Nations meeting on nuclear disarmament on the sidelines of the General Assembly. He was speaking on behalf of the Nonaligned Movement, which represents dozens of mostly developing countries.
Mr Rouhani also 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 programme.
Iran insists its nuclear programme 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 has imposed strict sanctions to punish Tehran to failing to halt its nuclear programme.
Israel is the only Middle East nation that has not signed the landmark 1979 Nuclear Non-Proliferation Treaty, and Mr Rouhani said that has prevented the region from establishing a nuclear-free zone.
"No nation should possess nuclear weapons, since there are no right hands for these wrong weapons," Mr Rouhani said.
A spokeswoman for the Israeli mission at the UN did not have an immediate comment, as the mission was closed for an official holiday.
In his debut on the world stage this week following his June election, Mr Rouhani and his government have shown urgency to revive the stalled nuclear negotiations and ease crippling international sanctions.
A meeting later is aimed at paving the way for the first round of substantive negotiations on the nuclear issue since April. The United States, Britain, France, Russia, China and Germany will participate, with European Union foreign policy chief Catherine Ashton serving as host of the meeting with Iranian foreign minister Javad Zarif.
Encouraged by signs that Mr Rouhani will adopt a more moderate stance than his hard-line predecessor, but sceptical that the country's supreme leader will allow a change in course, US 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, Mr Obama and other US officials have said Iran must prove its commitment with actions, not just words.
Mr Kerry predicted it would be a "good meeting". Asked what he would need to hear from the Iranians to show that they are serious, he said: "I'll let you know after they've been serious."