Iran and six world powers came to the table Monday for the first time in a year, exchanged pleasantries, but remained far apart on how deeply their talks should tackle the West's greatest concern -- Iranian nuclear activities that could make atomic weapons.

Tehran says it does not want atomic arms, but as it builds up its capacity to make such weapons, neither Israel nor the U.S. have ruled out military action if Tehran fails to heed U.N. Security Council demands to freeze key nuclear programs.

The long-term aim for the six nations is nudging Iran toward agreeing to stop uranium enrichment, which can make both fuel for reactors and the fissile core of nuclear arms.

Delegates from Iran, the European Union, the U.S., Russia, Britain, France and Germany hurried inside a conference center in Geneva to escape the pouring rain, and EU foreign policy chief Catherine Ashton met Saeed Jalili, Iran's chief negotiator, in the foyer.

As the doors closed to reporters Monday morning, the two had joined the other delegations sitting around a light brown oval table, with flags of their nations behind them.

"The two sides exchanged pleasantries -- the atmosphere was pleasant but businesslike," an official from one of the delegations said. The official, who asked for anonymity because his information was confidential, told The Associated Press the first hour was taken up by the six powers making a case for why they thought Iran's nuclear program needed to be discussed.

Iran's semi-official Fars news agency said Jalili began the meeting with a reference to the slaying last week of a senior Iranian nuclear scientist "and a strong condemnation of the terror act against him."

The attack, which left another scientists wounded, has burdened the atmosphere, with Iranian officials linking the West and the International Atomic Energy Agency to the assault.

Before the talks began, the chief negotiator from one of the six powers warned: "Don't expect much of anything," in a comment reflecting the deep divide separating the two sides. He also asked not to be named because he was not authorized to talk to the media.

Iran's defiance was highlighted Sunday when it announced it had delivered its first domestically mined raw uranium to a processing facility, claiming it was now self-sufficient over the whole enrichment process.

Salehi, head of the Atomic Energy Organization of Iran and the country's vice president, said Iran had for the first time delivered domestically mined raw uranium to a processing facility -- allowing it to bypass U.N. sanctions prohibiting import of the material.

Salehi said the delivery proved that the mysterious bombings which targeted the Iranian scientists would not slow the country's progress.

Iran acquired a considerable stock of yellowcake from South Africa in the 1970s under the former U.S.-backed shah's original nuclear program, as well as unspecified quantities of yellowcake obtained from China long before the U.N. sanctions.

Western nations said last year that Iran was running out of raw uranium as that imported stockpile diminished and asserted that Tehran did not have sufficient domestic ore to run the large-scale civilian program it said it was assembling.

"Given that Iran's own supply of uranium is not enough for a peaceful nuclear energy program, this calls into further question Iran's intentions and raises additional concerns at a time when Iran needs to address the concerns of the international community," said Mike Hammer, spokesman of the U.S. National Security Council.

But Salehi denied that local stocks were lacking and said Iran was now self-sufficient over the entire nuclear fuel cycle -- from extracting uranium ore to enriching it and producing nuclear fuel.

Since Iran's clandestine enrichment program was discovered eight years ago, Iran has resisted both rewards -- offers of technical and economic cooperation -- and four sets of increasingly harsh U.N. sanctions meant to force it to freeze its enrichment program.

Nations have a right to enrich domestically and Iran insists it is doing so only to make fuel for an envisaged network of reactors and not to make fissile warhead material. But international concerns are strong because Tehran developed its enrichment program clandestinely and because it refuses to cooperate with an IAEA probe meant to follow up on suspicions that it experimented with components of a nuclear weapons program -- something Iran denies.

Israel has threatened to attack Iran, even though Israel is believed to have stockpiled more than 200 nuclear weapons and it is not a member of the Nuclear Nonproliferation Treaty.

Western officials have urged Tehran to address international concerns about its nuclear activities.
U.S. Secretary of State Hillary Clinton has said it was up to Iran to restore trust about its nuclear intentions, urging it to come to Geneva prepared to "firmly, conclusively reject the pursuit of nuclear weapons."

But for Iran, the main issues are peace, prosperity -- and nuclear topics only in the context of global disarmament.

"Iran has not and will not allow anybody in the talks to withdraw one iota of the rights of the Iranian nation," President Mahmoud Ahmadinejad said earlier.