Approved unanimously by delegates at the 35-nation board meeting of the International Atomic Energy Agency (IAEA) on Saturday, the strongly worded resolution said the board "considers it necessary" that Iran should suspend all uranium enrichment and related programmes, which is technology that can be used for nuclear weapons.
It also expressed alarm at Iranian plans to convert more than 40 tonnes of raw uranium into uranium hexafluoride, gas that when spun in centrifuges turns into enriched uranium.
Tehran insists its nuclear activities are strictly tailored towards generating electricity. It played down the significance of the resolution.
The board also "strongly urged" Iran to meet all demands by the agency in its investigation of the country's nearly two decades of clandestine nuclear activity, including unrestricted access to sites, information and personnel that can shed light on still-unanswered questions on whether Tehran was interested in the atom for nuclear weapons.
It called on the IAEA head Muhammad al-Baradai to provide a review of the findings of the investigation into Iran's nuclear activities.
Crucial November meeting
"The issue is whether or not they're going to give up nuclear weapons. The ball is in Iran's court."
US Under-Secretary of State
Suggesting that Iran may have to answer to the UN Security Council if it defies the demands, the resolution said the next board meeting in November "will decide whether or not further steps are appropriate" in ensuring Iran complies.
The Americans, who accuse Iran of using the pretext of peaceful nuclear aims to acquire the technology to make weapons, praised the text as delivering a "stark" message to Iran.
"This resolution sends an unmistakable signal to Iran that continuing its nuclear weapons programme will bring it inevitably before the Security Council," chief US delegate Sanders said.
A senior US State Department official has said unless Tehran complies, it has to be brought before the UN Security Council when the board next meets in November.
"The issue is whether or not they're going to give up nuclear weapons" by the November meeting, US Under-Secretary of State John Bolton said. "The ball is in Iran's court."
IAEA chief al-Baradai described the text as reflecting "the collective will of the international community", adding: "The resolution is very clear as to what is expected of Iran in the next few months."
The phrasing accepted left it up to the board to debate what action, if any, to take when it reconvenes on 25 November if Iran is found to have ignored the demand to freeze enrichment or other conditions.
Iran's chief delegate Mousavian
said the US' goals were not met
Iran's chief delegate to the meeting asserted that Washington was frustrated in its main goals of "putting [a] deadline of 31 October [and] second, an automatic trigger mechanism".
"Both were neglected, and we have nothing like this in the resolution," Hussain Mousavian said.
Iran says it is honouring a pledge not to put uranium hexafluoride gas into centrifuges, spin it and make enriched uranium.
But the resolution also calls for a halt to related activities, including making, assembling and testing centrifuges and producing uranium hexafluoride.
Iran is not prohibited from enrichment under its obligations to the Nuclear Non-proliferation Treaty.
However, it has faced growing international pressure to suspend such activities as a good-faith gesture, and the resolution went further by demanding a stop to enrichment and related activities.
"This resolution sends an unmistakable signal to Iran that continuing its nuclear weapons programme will bring it inevitably before the Security Council"
chief US delegate
Approval of the resolution followed days of backdoor negotiations and resistance by non-aligned countries that saw their own right to enrichment for peaceful use threatened.
Before the approval, Mousavian, the chief Iranian delegate, had held out the possibility of meeting the resolution's key demand.
Iran's "decision-makers will decide about the main request, full suspension", in the next few days, he said.