Since the International Atomic Energy Agency (IAEA) began investigating Iran's nuclear program in February 2003, and as more and more details of Tehran's atomic activities have emerged, the sense of alarm has become increasingly widespread.
Iran has demonstrated a proven ability to enrich uranium, and has been developing an infrastructure that could eventually produce large quantities of weapons-grade material. If left unhindered by international controls, Tehran could reach the nuclear threshold in just a few years' time, officials, diplomats, and analysts say.
"They know how to drive, and now they just need to build a car," said a senior Western official in Vienna familiar with the Iranian situation. "Provided they don't hit any bottlenecks, they are about two to five years away," the official added. More conservative estimates say they could be a decade away.
Over the past two years, the international community has been trying to create as many bottlenecks as possible.
Ever since Iran admitted in October 2003 to conducting 18 years of clandestine research in uranium enrichment -- a process that produces fuel that can be used in nuclear weapons -- the nation's nuclear industry has come under unprecedented scrutiny.
Some familiar with the issue say Iran appears to have already crossed a critical threshold in know-how and soon could be in position to develop a nuclear weapon
In an effort to avoid UN Security Council sanctions, Iran signed an agreement with the European Union on 14 November to suspend activities related to uranium enrichment, a process that can produce fuel for nuclear weapons, and the IAEA agreed to monitor the freeze.
But despite the intense international spotlight, officials and diplomats familiar with the issue say Iran appears to have already crossed a critical threshold in know-how and soon could be in position to develop an atomic weapon.
"They are just sitting on a nice capability to enrich uranium," a Western official close to the IAEA said. "Right now, Iran can produce small amounts of fissile material. But once they can produce large amounts, the bomb is just months away."
Although oil-rich, Iran insists its nuclear program is solely to generate electricity.An Emerging Nuclear Infrastructure
Among Iran's known facilities, officials are most troubled by an underground centrifuge enrichment plant in Natanz, 200 miles south of Tehran, which Iran kept secret until the National Council for Resistance of Iran, an exile opposition group, exposed it in August 2002.
In February 2003, IAEA inspectors discovered highly enriched uranium there and at another site. Inspectors later discovered that Iran had also separated small amounts of plutonium, another pointer toward a potential weapons program.
Enriching uranium and separating plutonium are allowed under the nonproliferation treaty, as long as they are reported to the IAEA and open to agency safeguards and inspections to assure that they are for peaceful purposes. By covering up such activities, Iran caused many who had previously given the country the benefit of the doubt to suspect it was trying to develop nuclear weapons.
Before enrichment work there was suspended and put under IAEA safeguards, a pilot plant at Natanz had approximately 200 centrifuges installed. A second large-scale plant at Natanz that is under construction could, at full capacity, house as many as 50,000 centrifuges and produce enough bomb-grade uranium for 15 to 20 nuclear weapons a year, according to some analysts.
Iran has also acquired a design for and begun research and development on the advanced P-2 centrifuge, which could enrich uranium faster than the older P-1 design used at Natanz. Officials familiar with the investigation into Iran's nuclear program say Iran got the P-2 centrifuge design from Abdul Qadeer Khan, the founder of Pakistan's nuclear program, who also provided similar nuclear know-how to Libya and North Korea.
But what worries officials most are not the facilities they know about, but those that many suspect are still undeclared and hidden. Officials are particularly concerned about Lavizan, a military research site in northern Iran, a facility that the United States alleges housed a nuclear facility.
Satellite images showed that buildings, which had been there in August 2003, had been razed to the ground by March 2004 and that topsoil had been taken away. The Washington-based Institute for Science and International Security (ISIS) think tank said on its website that razing the buildings was suspicious "because it is the type of measure Iran would need to take if it was trying to defeat the powerful environmental-sampling capabilities of IAEA inspectors." Environmental sampling involves samples taken to find traces of radiation.
As tension mounted over Iran's nuclear program, Tehran announced in September that it had tested what it called a new "strategic missile" and delivered it to its armed forces. Iran currently has an arsenal of Shihab-3 missiles, which according to published reports have a range of between 1,300 and 1,500 kilometers -- meaning it could hit Israel and parts of Europe -- and is capable of carrying a 700-1,000-kilogram warhead.Responses And Consequences
The specter of a nuclear-armed Iran, which could threaten Israel, set off a dangerous arms race, and further destabilize the Middle East, is something the United States and its allies are furiously seeking to prevent.
The United States has pushed for Iran to be reported to the UN Security Council, which could impose sanctions, while the European Union has offered Tehran a series of economic and political incentives to give up its nuclear ambitions.
Israel has also made it clear that it will not tolerate a nuclear-armed Iran and has strongly hinted that it may use military strikes to eliminate nuclear sites there should diplomacy fail. Israel plans to buy about 5,000 U.S.-made smart bombs, including 500 1-ton bunker busters that can penetrate 2-meter-thick concrete walls, according to recent press reports.
But many diplomats and officials fear that neither sanctions nor military strikes would solve the issue.
Should the Security Council eventually impose sanctions, an increasingly isolated Iran may pull out of the Nuclear Nonproliferation Treaty (NPT), as North Korea did last year and Tehran has repeatedly threatened to do, and pursue a weapons program unfettered. And while Iran would stand to lose a lot in terms of trade and investment if it withdrew from the treaty, such a defiant move could boost Tehran's prestige in the region. ''If Iran dropped out of the NPT, you would have at least 30 countries, mostly in the Middle East, cheering them on," a senior Western official close to the IAEA said.
Trying to solve the issue militarily, officials say, is also fraught with peril. Officials have voiced concerns that in the event of a military strike Iran might attempt to further subvert the situation in neighboring Iraq by influencing Shi'ite Muslims there.
Moreover, U.S. military intelligence has simulated a U.S. strike on Iran's nuclear facilities but they were unhappy with the war game's outcome because they could not prevent the conflict from escalating.
Analysts have also warned it would be difficult to hit Iran's nuclear sites with absolute confidence, since they are in hardened facilities and the locations of all of them are not known.
"You could have failed to decisively set back the program but at the same time prompt Iran to take a number of steps in retaliation, including to destabilize the situation in Iraq," said Robert Einhorn, who served as the Clinton administration's assistant secretary of state for nonproliferation.
Analysts say that the strongest card the international community has to play is the fact that Iran craves international respectability and badly needs increased trade and investment -- and would risk severe diplomatic ostracism, or worse, by going nuclear.
"Iran can be a pariah with nuclear weapons, or it can choose to become a respected, integrated member of the international community," Einhorn said. "Iran is not North Korea. The North Korean regime may want isolation," he added.