A series of technical problems at the central Iranian nuclear facility at Natanz appear to have slowed down its nuclear fuel-enrichment program and put on hold plans to expand it, it was reported on Tuesday.
In April, Iran succeeded in operating a cascade of 164 centrifuges, an amount sufficient to fuel nuclear power plants, but far short of the threshold of several thousand needed to build a nuclear bomb. A second round of feeding uranium into centrifuge enrichment machines began on June 6.
According to one diplomat, several unconfirmed reports state that the first cascade, basis for Iranian plans to install 3,000 centrifuges by 2007, had a failure rate of up to 50 percent, Channel 2 reported.
He said the centrifuges seemed to be showing fragility after being spun at supersonic speeds, and the nature of materials injected into them - which could involve impurities in the uranium - could be damaging too.
Meanwhile, Iran ruled out responding this week to international incentives to suspend its nuclear program, saying Tuesday that the offer contains too many "ambiguities."
Ali Larijani, Teheran's top nuclear negotiator, said after meeting with European Union foreign policy chief Javier Solana that the "ambiguities must be removed first in order to have serious talks."
His comments dashed any hope that that Iran would meet a Wednesday deadline on a six-nation offer of incentives aimed at dissuading Tehran from uranium enrichment.
Foreign ministers from the six powers that crafted the proposal - the five permanent UN Security Council members plus Germany - are to meet Wednesday in Paris. The six are pushing for an agreement before the July 15-17 Group of Eight summit in Russia.
Iran repeatedly has said it will not respond to the offer before August and Larijani warned that talks on his country's atomic program will be a "long process."
The negotiator refused to elaborate on the nature of the perceived ambiguities, but he called on the European Union, United States, Russia and others to be patient.
"I see no reason for being skeptical. We must allow more time for negotiations to work,'' Larijani told reporters after meeting with Solana. ``All matters must be discussed and all concerns must be addressed."
Larijani warned the United States and others against sending the matter to the Security Council for possible sanctions, calling it "the wrong way" to solve the impasse.
"It is not difficult to disrupt negotiations by making harsh comments," Larijani said.
Some Western officials have threatened to restart efforts to punish Iran through possible sanctions unless Teheran stops uranium enrichment and agrees to talks by Wednesday.
Solana offered little comment on the meeting, which lasted around four hours. "We will make (an) analysis and we will see how to proceed," Solana said.
Solana had been hoping for a positive reply from Larijani on the offer of economic and trade rewards, nuclear expertise and reactors in exchange for a pledge by Iran to suspend uranium enrichment activities during nuclear talks.