Iran has opened a summit bringing together more than 120 nations that call themselves "non-aligned", with an appeal to rid the world of nuclear weapons even as the West suspects Tehran is seeking its own atomic arms.
Among those expected to attend the summit of the Non-Aligned Movement (NAM), which opened on Sunday but will officially begin on Thursday, include Ban Ki-moon, the UN secretary-general, and Manmohan Singh, the Indian prime minister.
India remains an important Iranian oil customer as Tehran battles Western sanctions over its nuclear programme.
Iran will seek to use the week-long gathering, capped by a two-day summit of various leaders, as a showcase of its global ties and efforts to challenge the influence of the West and its allies.
Ali Akbar, the Iranian foreign minister, opened the gathering by noting commitment to a previous goal from the non-aligned group, known as NAM, to remove the world's nuclear arsenals within 13 years.
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"We believe that the timetable for ultimate removal of nuclear weapons by 2025, which was proposed by NAM, will only be realised if we follow it up decisively," he told delegates.
Iran insists its nuclear programme is intended for generating energy for civilian use, but the US and its allies fear that Tehran's uranium enrichment could eventually lead to warhead-level material.
Tehran is groaning under heavy sanctions imposed on its banking and oil exports, measures that the West hopes will wring concessions.
Israel, which says it faces an existential threat from Iran, has hinted at a military option if diplomacy and economic pressures fail to curb Tehran's nuclear ambitions.
Salehi criticised Israel for remaining outside the UN main treaty governing the spread of nuclear technology. Israel refused to discuss the full range of its military capabilities, but it is widely believed to have a nuclear arsenal.
Iranian ally North Korea has withdrawn from the Nuclear Non-Proliferation Treaty. The North Korean foreign minister Paek Nam Sun arrived in Tehran on Sunday to attend the meetings.
Meanwhile, Iranian news agencies have said the prime minister of Iranian ally Hamas has not been invited to the meeting.
The semiofficial Mehr and ISNA quoted Mohammad Reza Forqani, the summit spokesman, as saying Ismail Haniyeh was not invited to the meeting.
But Haniyeh's office in the Gaza Strip said he planned to travel to Tehran on Monday as guest of Mahmoud Ahmadinejad, the Iranian president.
The conflicting reports over Haniyeh's plans reflect complications with the Palestinian delegation for the NAM gathering.
The office of Palestinian President Mahmoud Abbas said he would not attend if rival Haniyeh also took part.
Iranian-backed group Hamas controls Gaza while Abbas' administration governs the West Bank.
The NAM, which boasts 120 members and 17 observer countries, is a group of states considering themselves not aligned formally with or against any major power bloc.