Obama said while all nations had the right to peaceful nuclear energy, those with nuclear weapons should move towards disarmament. At the same time, countries without nuclear weapons must forsake them.

'That compact has largely held for decades, keeping the world far safer and more secure. And that compact depends on all nations living up to their responsibilities,' the US president said.

According to the British premier, Iran's nuclear programme was the most urgent proliferation challenge that the world faces today.

'On October the 1st, Iran must now engage with the international community and join the international community as a partner. If it does not do so, it will be further isolated.'

Their comments came a day after the council unanimously passed the resolution aimed at ensuring full compliance with international arms pacts from countries like North Korea and Iran which have either banned inspectors or severely limited their access.

Iranian President Mahmoud Ahmadinejad says his country's nuclear programme is peaceful and limited to generating energy, even as most rich countries, led by the US, say Tehran's eyes are set at building atomic weapons.