World powers yesterday adopted a landmark resolution seeking to rid the planet of nuclear arms at an unprecedented Security Council summit hosted by US President Barack Obama.

"Although we averted a nuclear nightmare during the Cold War, we now face proliferation of a scope and complexity that demands new strategies and new approaches," Obama told the 15-member body.

"Just one nuclear weapon exploded in a city, be it New York or Moscow, Tokyo or Beijing, London or Paris, could kill hundreds of thousands of people."

The talks come as Iran's suspect atomic program has once again been thrust into the spotlight, with world powers warning more sanctions could follow if Tehran refuses to comply with UN demands to rein in its nuclear ambitions.

The Security Council resolution, adopted unanimously, commits member nations to work toward a world without nuclear weapons and endorses a broad framework of actions to reduce global nuclear dangers.

Quoting former US president Ronald Reagan, Obama told the meeting that "a nuclear war cannot be won and must never be fought."

"And no matter how great the obstacles may seem, we must never stop our efforts to reduce the weapons of war," he urged, as he became the first American president to chair a meeting of the UN Security Council.

"We must never stop until all until we see the day when nuclear arms have been banished from the face of the earth. That is our task. That can be our destiny."

US officials have stressed the aim of the summit is to reinvigorate the nuclear Non-Proliferation Treaty (NPT), which will be the subject of a key review conference next year.

The Security Council meeting comes as Iran's President Mahmoud Ahmadinejad has offered landmark talks between Iranian and US experts for the first time to allay fears about his country's nuclear programme.

"Why not just let them sit and talk and see what kind of capacity they can build? I think it is a good thing to happen," Ahmadinejad said in an interview with the Washington Post and Newsweek.

And he said Iran would offer to purchase enriched uranium for medical purposes from the United States at upcoming talks with six world powers on October 1 in Geneva.

Russia on Wednesday signalled it could back sanctions if Tehran fails to make concessions at the October 1 meeting with the five permanent members of the UN Security Council -- which are all declared nuclear powers -- plus Germany.

India and Pakistan are also nuclear powers, while North Korea has carried out nuclear tests.

The annual UN General Assembly was to be addressed later Thursday by Israeli leader Benjamin Netanyahu, whose country is widely believed to be the Middle East's sole, if undeclared, nuclear power.

The resolution urges all states to comply with the obligations of the NPT, to refrain from conducting nuclear test explosions and ratify the Comprehensive Test Ban Treaty (CTBT).

It also calls for talks on drafting a treaty to ban the production of fissile material for nuclear weapons, and urges those nations, which are not members of the nuclear Non-Proliferation Treaty to join it as non-nuclear states.

It also includes provisions to deter countries from leaving the NPT.

The text makes no direct reference to Iran and North Korea but points to Security Council resolutions enjoining Tehran to halt sensitive nuclear fuel work and Pyongyang to dismantle its nuclear weapons programme.