A leading independent policy analysis group in London says Iran faces technical difficulties in producing nuclear weapons, which could take up to 10 to 15 years to overcome. Iran's nuclear program is on top of the agenda for the International Atomic Energy Agency board meeting later this month.

A new report by the International Institute for Strategic Studies in London says it may take years before Iran can become a nuclear power.

Gary Samore, one of the authors of the study and one-time security adviser to former U.S. President Bill Clinton talked to VOA about the findings. "There are a number of different problems the Iranians are having producing high quality uranium hexafluoride feed material and in installing and testing centrifuge machines," he said, "and on the basis of that judgment we argue that it would take Iran at least five years to produce enough weapons grade uranium for a single weapon if it made a political decision".

Mr. Samore said developing full nuclear capabilities could take Iran as long as a decade or 15 years.  It is widely reported that an unpublished U.S. National Intelligence Estimate projects that Iran is 10 years away from building a nuclear bomb.

Iran insists its program is only for peaceful purposes, but it has acknowledged a long history of undeclared work.

The IAEA, which has been investigating Iran's nuclear capabilities for years, says it is not in a position to give assurances to the world that Tehran's program is peaceful.

The U.S. government accuses Tehran of stalling in negotiations on its nuclear program with European nations and Mr. Samore agreed, saying time is on Iran's side. "Two and a half years ago the Iranians were very nervous about being next on Washington's hit list after Iraq, and they were very worried about referral to the Security Council, and so as a consequence they were willing to accept a number of limits on their program," said Mr. Samore. "I think that's faded now, and currently I think Tehran calculates it's in a stronger position because the U.S. is hamstrung in Iraq and because the tight oil market reduces the risk of strong international economic sanctions."

The United States says the most recent report on Iran by the International Atomic Energy Agency backs up its concerns that Iran is proceeding with a nuclear weapons program.

A senior U.S diplomat based in Vienna, who did not want to be named, told VOA, "unless Iran stops uranium conversion and cooperates with the IAEA and returns to the negotiating table, then we will support the Europeans in sending the matter to the U.N. Security Council."

But Russia, which holds veto power on the Security Council, says it would oppose such a move at this stage. There are other members on the 35-nation IAEA governing board who are also not convinced that the Iran case is urgent and the new report by the International Institute for Strategic Studies would appear to support their views.

The IAEA board of governors meets in Vienna on September 19 to decide what action to take on Iran.