EU warns Iranians about violating spirit of nuclear freeze

Britain, France and Germany "are going to read the riot act to the Iranians," a diplomat close to the talks told AFP.

The European trio, leading negotiations for the European Union, will be following advice from UN nuclear watchdog chief Mohamed ElBaradei "who has warned Iran in two letters in December and January" about quality control work on centrifuge parts despite the freeze, said the diplomat, who who asked not to be named.

Centrifuges are used to spin uranium gas in order to turn out enriched uranium, which can be used as fuel for nuclear power plants but also as the explosive core of atomic bombs.

Iran, which in November pledged to suspend all uranium enrichment-related activities, has since then carried out maintenance work on centrifuge piping at an enrichment plant at Natanz, including taking parts such as valves to another location, Farayand, to test them, diplomats said.

"Maintenance work is totally permissible under the terms of the suspension. What you can't do is quality control work," the diplomat said.

"This is coming close to being a breach of the suspension agreement but still short of forcing a breakdown in the talks," the diplomat said.

The diplomat said this is how the Iranians have acted on other sensitive matters in the two years that ElBaradei's International Atomic Energy Agency (IAEA) has been investigating Iran for violations of international nuclear safeguards.

"The Iranians did not report their quality control work. IAEA inspectors came across it by chance in their verification of centrifuge components in Farayand," the diplomat said.

The Geneva talks are being conducted in the strictest secrecy, with diplomats stressing that the long-term negotiations require confidence-building on both sides.

Iran is waiting for incentive rewards, such as entry into the World Trade Organisation, for its temporarily suspending enrichment.

The United States would have to support this but it is not part of the European initiative and leads the West in charging that Iran is secretly developing nuclear weapons.