GENEVA: World powers held their first meeting in 14 months with Iran over its disputed nuclear programme on Monday, sounding out Tehran's intentions after it claimed to have taken a new step in making fissile material.

Just a day ahead of the talks, Tehran raised the stakes by revealing that it had mined and produced its first home-grown batch of uranium yellowcake instead of seeking to import new supplies.

That triggered statements of concern in Washington and Europe ahead of the meeting in the Swiss city of Geneva between the European Union's top diplomat, Catherine Ashton, and Iran's chief negotiator, Saeed Jalili.

The negotiations, scheduled to last two days, began promptly Monday morning at the building of the Swiss mission to the UN, with Ashton, Jalili and officials from Britain, China, France, Germany, Russia and the United States sitting around a table, Swiss organisers said.

Jalili began talks by making a strong protest against the recent assassination of a top nuclear scientist in Tehran, according to Iranian sources.

A diplomat close to the world powers said before the talks opened: “We are expecting a serious response from the Iranians.We do not know what is Iran's state of mind.”

A Western official said that a second plenary would be held later Monday after the talks broke for lunch, while another diplomat close to the world powers added that bilateral meetings with the Iranians would also be held.

The meeting, a mirror image of the last attempt in October 2009 to temper Iran's uranium enrichment drive, is taking place amid tougher international sanctions on Tehran and few hopes that a deal can be struck.

Tehran maintains that it is seeking nuclear energy for peaceful purposes but Western countries have accused the Islamic republic of engaging in a covert programme to build nuclear weapons.

Before Sunday's announcement by Iranian atomic chief Ali Akbar Salehi European sources hoped the meeting would help re-engage the Iranians even if it did not produce instant results.

But Iranian leaders, led by President Mahmoud Ahmadinejad, have reiterated in recent days that the country's nuclear plans were non-negotiable.