GENEVA - The United States said it held the highest level direct talks with Iran in three decades on Thursday to try to put to rest Western suspicions Tehran is planning a nuclear bomb.

The significant bilateral conversation took place during talks between Iran and six world powers near Geneva, an official at the talks said. Iran declined to confirm the two-way meeting.

The negotiations outside Geneva, also attended by Britain, France, Germany, Russia and China, took place against a backdrop of renewed international concern prompted by Iran's revelation it has a second uranium enrichment facility.

Washington had said it would not threaten further sanctions against Tehran at the one-day meeting but had prepared them in case the discussions made no progress.

This can't be a phony process, a senior U.S. official said in Washington.

Tehran says its nuclear program is designed purely for generating electricity and had ruled out discussing it, saying the talks should focus on issues like Afghanistan instead.

But a Western diplomat close to the meeting said Iran's nuclear negotiator had touched on it in his opening statement.

A Western diplomat said the issue of the second enrichment facility at Qom had been raised. The West wants Iran to allow immediate U.N. inspections at the plant, which Tehran revealed last week, and give access to documents and employees.

The diplomat said it was not yet clear if the Iranians would compromise on the wider issue of suspending uranium enrichment, as demanded by five U.N. Security Council resolutions.

Iranian state television said later the two sides would meet again this month. There was no immediate confirmation.

'THE ENGAGEMENT TRACK'

Ali Akbar Javanfekr, an adviser to President Mahmoud Ahmadinejad, warned the West against using what he called the logic of force in comments to Reuters.

An Iranian official who declined to be named said Iran wanted the talks to succeed. We want logic to dominate the atmosphere of the talks, the official said.

In Washington, senior Obama administration officials said the United States would not threaten Iran with fresh sanctions.

But one official said the United States has been preparing a range of areas in which to pursue sanctions if Tehran ignores Western entreaties about its nuclear program.

These could be applied through the U.N. Security Council or by individual states. Experts believe they may be targeted at the energy sector.
You're in a much better position to prepare the ground on the pressure track if you have demonstrated unmistakably that you're doing everything you can on the engagement side, one official said.

The meeting at the elegant villa made available by the Swiss for decades to bring foes together was the first time a U.S. official was a full participant in such talks.

Undersecretary of State for Political Affairs William Burns, head of the U.S. delegation, also met Iran's chief nuclear negotiator Saeed Jalili separately, U.S. officials said.

There was a meeting with the Iranians, said Robert Wood, a spokesman for the U.S. State Department.

They were the highest level U.S.-Iran talks in nearly 30 years. At a similar meeting in Geneva in 2008 Burns left the room to avoid having to shake hands with Jalili, according to diplomats at those talks.

Washington severed relations with Tehran in 1980 during a hostage crisis in the wake of Iran's Islamic Revolution.

The administration of former President George W. Bush reluctantly began to take part in multilateral talks with Iran toward the end of his presidency. President Barack Obama, Bush's successor, has said he wants to improve U.S.-Iranian ties but Tehran has reacted coolly to his overtures.

WEST EYES RUSSIAN, CHINESE REACTION

Professor Mohammad Marandi, head of North American studies at Tehran university, said the Iranians expected the six powers to accept it had a right to a nuclear program.

Iranian President Mahmoud Ahmadinejad said in New York last week his delegation would ask at the Geneva meeting that Iran be allowed to buy enriched uranium for medical purposes from the United States or any other country prepared to sell it.

A U.S. official said Washington would make clear that it was not prepared to sell Iran any uranium.

The Western powers also want to gauge Russian and Chinese reaction to last week's announcement that Tehran had been concealing the uranium enrichment plant at Qom. Western diplomats said Moscow and Beijing seemed to share their concern.

The Russians and Chinese don't want a nuclear-armed Iran, a Western diplomat told Reuters. They've made that clear.

NATO Secretary-General Anders Fogh Rasmussen said in London he hoped Iran realized it had to abandon its nuclear plans.

Recent events including the fact that Iran had not declared the existence of a nuclear site testifies to the importance of this issue and stresses the need for an increased international, political and diplomatic pressure on Iran, he told reporters.

The senior U.S. official said Thursday's talks could not be an open-ended process or talks just for the sake of talks, but that the issue was likely to need more than one meeting.
Iran's English-language Press TV said later: Iran and the 5+1 (powers) agree to hold talks again before the end of October. It did not give a source. Obama has said he wants progress before the end of the year.

(Additional reporting by Parisa Hafezi and Stephanie Nebehay in Geneva, Steve Holland in Washington, Fredrik Dahl in Tehran and Jonathan Saul in London; writing by Philippa Fletcher; editing by Dominic Evans)