Iran on Thursday rejected as "totally untrue" allegations by France and Britain that it is trying to acquire nuclear weapons, insisting it was ready to engage in "serious talks."

Iran's UN mission said allegations made by French President Nicolas Sarkozy and British Prime Minister Gordon Brown at Thursday's Security Council summit on nuclear proliferation "are totally untrue and without any foundation."

Tehran's commitment to non-proliferation "remains intact," it said in a statement, reiterating the Islamic Republic was ready to "engage in serious and constructive negotiations with interested parties, based on respect, justice, rights of nations and collective commitments."

In remarks prepared for delivery at the council meeting, Sarkozy was to have said: "In violation of five UN resolutions, Iran is pursuing its nuclear proliferation activities.

"No one can seriously believe that the aims of these activities are peaceful.

"Iran is amassing centrifuges and enriched uranium. It does not need them. So what is its purpose? It is developing a ballistic arsenal that already threatens Europe, including Russia. What for?" the text said.

But the French leader widely departed from his prepared remarks, and did not make those exact comments to the 15-member body as it adopted a landmark resolution aimed at getting rid of nuclear arms.

Instead the French leader told the council: "Iran since 2005 has flouted five Security Council resolutions.

"There comes a time when the stubborn facts will compel us to make a decision. If we want a world without nuclear weapons in the end, let us not accept violations of international rules."

The Iranian mission hit back: "Allegations made by the French president against Iran's nuclear program are a preposterous attempt to disguise the abysmal record of France in non-compliance with its nuclear disarmament obligations."

Brown meanwhile told the council that Iran and North Korea were taking "steps to develop nuclear weapons in a way that threatens regional peace and security.

"Today, I believe we have to draw a line in the sand. Iran must not allow its actions to prevent the international community from moving forward to a more peaceful era," he said.

"And as evidence of its breach of international agreements grows, we must now consider far tougher sanctions together," the British leader added.

Reacting to Brown's comments, Tehran accused London of "deliberately" failing to take "practical steps to accomplish the total elimination of its unjustifiable nuclear arsenals under article VI of the NPT."

In an interview with the Washington Post and with Newsweek magazine, Iranian President Mahmoud Ahmadinejad said Iranian and US nuclear experts should meet to allay fears about his country's nuclear program.

"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.

He also said Iran would offer to purchase enriched uranium to help develop products for medical purposes from the United States at talks with six major powers in Geneva on October 1.