The three-member legal team from the International Atomic Energy Agency was meeting Iranian government lawyers, said Saber Zaeimian, spokesman of the Atomic Energy Organization of Iran.
The United States has accused Iran of running a clandestine nuclear weapons program and wants the IAEA to declare Tehran in violation of the non-proliferation treaty. Iran insists its nuclear program is for peaceful, electrical power purposes.
But in a report Monday, the Los Angeles Times said Iran "appears to be in the late stages of developing the capacity to build a nuclear bomb."
The Times said its three-month investigation found that Iran has been involved in a pattern of activity that has concealed weapons efforts from international inspectors.
The newspaper — citing sources ranging from previously secret reports, international officials, independent experts and Iranian exiles — reported that Iran made use of technology and scientists from Russia, North Korea, China and Pakistan to bring it closer to building a bomb than Iraq ever was.
Among its findings, the paper said a confidential French report concluded that, "Iran is surprisingly close to having enriched uranium or plutonium for a bomb."
The paper also reported that samples of uranium taken by arms inspectors in June tested positive for enrichment levels high enough to be consistent with an attempt to build a nuclear weapon.
Reacting to the Times story, State Department spokesman Philip Reeker said the U.S. has "long believed that Iran is pursuing a clandestine nuclear weapons program under a cover of a supposedly peaceful, civil nuclear energy program."
"Iran's clandestine nuclear program represents, we believe, a serious challenge to regional stability and frankly, to the entire international community and to the global nonproliferation regime," he said. "We have been committed to using all available tools to stop Iran's nuclear weapons program."
Foreign officials told the Times the CIA has discussed plans for possible airstrikes on Iranian nuclear facilities. The CIA would not confirm that claim.
Commenting on reports of Iranian nuclear efforts, White House spokesman Scott McClellan said the government is "working with the IAEA to make sure that they do not continue on this course, which is unacceptable."
Iran has said it would agree to unfettered inspections if it is granted access to advanced nuclear technology as provided for under the treaty. Tehran says Washington is keeping Iran from getting that technology.
Monday's talks focus on an additional protocol to the Nuclear Non-Proliferation Treaty allowing open inspections that the IAEA is pressing Tehran to sign, the official Islamic Republic News Agency cited Zaeimian as saying.
In recent weeks, conservatives in Iran's Islamic establishment have said Iran would withdraw from the treaty altogether if the IAEA forces Iran to sign the protocol.
Iran's Foreign Ministry spokesman Hamid Reza Asefi has said Iran's withdrawal was out of question.
The Times reported that some analysts see Iran as little as two to three years away from building a bomb.
Among the allegations in the Times story, which were based on secret reports and interviews with intelligence sources, Iranian exiles and weapons experts, were:
- That Iran has several weapons research laboratories at a plant disguised as a watch-making factory. It barred inspectors from seeing parts of that plant.
- That Iran secretly imported 1.8 tons of nuclear material from China in 1991, and used some it to make uranium metal, which would only be useful for weapons production.
- That Pakistan offered to sell nuclear weapons technology to Iran as early as 1989.
- That so many North Korean scientists are working on nuclear projects in Iran that a resort has been reserved exclusively for their use.
- That Iran has told Russia it wants to develop its own uranium fuel for a reactor Russia is building, a possible sign that Tehran intends to enrich the uranium to weapons grade.