U.N. Checkup On Iran Nuke Sites

Five U.N. nuclear inspectors arrived Monday to try to confirm whether Iran has stopped suspicious nuclear activities — including the building of centrifuges for uranium enrichment.

Mohammad Saeedi, a top Iranian nuclear official, told The Associated Press the experts from the United Nation's International Atomic Energy Agency arrived for a series of meetings and inspections.

The visit coincides with a call by Iranian radicals that their government should defy the U.N. nuclear agency, expel U.N. inspectors and resume uranium enrichment. The Iranian government, though, appears determined to stick to a more moderate approach in hopes of avoiding international isolation.

The United States and other nations accuse Iran of having a covert nuclear weapons program and are pushing the United Nations to impose sanctions. Tehran insists its nuclear activities are peaceful and for the purpose of generating electricity.

Saeedi said that to win "greater international trust," Iran stopped building and assembling centrifuges Friday, as it promised during a one-day visit last week by IAEA chief Mohamed ElBaradei.

It was the second such promise: Iran said March 29 that it had already stopped building centrifuges for uranium enrichment.

ElBaradei had welcomed the centrifuge announcement and said the inspectors who arrived Monday would try to verify that all uranium enrichment activities have stopped.

During ElBaradei's visit, Iran also committed to meeting deadlines on disclosing the source of traces of weapons-grade uranium found here and answering questions on its recently discovered program to make advanced P-2 centrifuges to enrich uranium, possibly to weapons grade.

Iranian hard-liners have accused ElBaradei of being "America's agent" and say that by giving in to the IAEA, Iran is giving in to U.S. demands to surrender nuclear technology.

"The only logical option is to resume uranium enrichment, expel IAEA inspectors and withdraw from (the Nuclear Nonproliferation Treaty) if the (IAEA) continues to illegally deny Iran its rights," hard-liner Hossein Shariatmadari wrote in an editorial last week in his newspaper, Kayhan. Shariatmadari is close to Iran's supreme leader, Ayatollah Ali Khamenei, who has the final say on all state matters.

Iran says it's losing its patience and wants the IAEA to remove Iran's nuclear dossier from its agenda by June. Tehran's top nuclear negotiator, Hasan Rowhani, said last week Iran will "definitely react" if its nuclear dossier is not closed by then, but said, "I don't think the reaction will be to withdraw from NPT."

In a report last year the IAEA determined that Iran had concealed aspects of its nuclear program. But the IAEA did not conclude that Iran had a weapons program. The United States pressed for a harsher conclusion. The IAEA has been divided over whether to refer the case to the Security Council, which could mete out sanctions for Iran failing to comply with the NPT.

Under pressure, Iran last year signed a special annex to the treaty in which it agreed to new nuclear inspections. Those inspections have uncovered traces of enriched uranium on equipment, which Iran said came from the countries that produced the equipment.

Inspectors also found that sophisticated centrifuges were being developed at an Iranian air force base, suggesting links between Iran's civilian nuclear program — which has been openly supported by Russia — and its alleged military program. Tehran denies any connection.

In one of a series of disputes, Iran and the IAEA disagreed over the meaning of an Iranian pledge to halt uranium enrichment. Tehran at first insisted that the pledge only covered work on uranium itself, and vowed to continue making the equipment used in that work. The IAEA protested, and Tehran has since said it will halt both.

Centrifuges are used to separate the two isotopes of natural uranium and increase the concentration of the isotope that is used in nuclear fission, which is the lighter of the two. By spinning uranium gas very quickly, the isotopes can be separated and the lighter one extracted and used.

This process is called enrichment. Material for nuclear bombs tends to be much more enriched that material for power plants.

The Iran nuclear dispute has unfolded during a complicated period in U.S.-Iranian relations.

Washington has labeled Iran a member of the "axis of evil" and dubbed it a sponsor of terrorism. But Iran has not actively opposed U.S.-led wars in two neighboring countries, Afghanistan and Iran.

Officials in both governments — enemies since the 1979 Islamic revolution in Iran — have hinted at the possibility of dialogue.