TEHRAN, Iran (AP) _ Iran has doubled its capacity to enrich uranium by successfully executing the process with a second network of centrifuges, a semiofficial news agency reported Friday, sending a defiant new message to the U.N. Security Council.
Council members are working on a draft resolution that would impose limited sanctions on the Islamic republic because of its refusal to cease enrichment, a process that can produce fuel for a civilian nuclear reactor or fissile material for a warhead.
The Iranian Students News Agency quoted an anonymous official as saying Iran has successfully begun injecting gas into a second network of centrifuges.
``We are injecting gas into the second cascade, which we installed two weeks ago,'' the official said, according to ISNA.
The news agency said the second cascade had doubled Iran's capacity to enrich uranium.
``We have already exploited the product of the second cascade,'' the official was quoted as saying.
Iranian authorities are believed to leak ISNA information that they want published but consider too sensitive for release to official media.
The State Department said it was up to the International Atomic Energy Agency to assess the reports. ``I cannot confirm those reports. We are not on the ground,'' State Department spokesman Sean McCormack said.
President Bush said that regardless of the accuracy, it was ``unacceptable'' for Iran to have a nuclear weapon and the report underscored the need for the United States and its allies to redouble its effort to stop Iran from developing nuclear ambitions.
The U.N. Security Council has demanded that Tehran cease all enrichment-related activities amid fears by the U.S. and its allies that Iran is seeking to develop a program that can make weapons-grade uranium for nuclear warheads. The Iranians claim their nuclear program is peaceful.
France's Foreign Ministry called Iran's expansion of its nuclear program a ``negative signal'' that should be taken to account at U.N. talks over possible sanctions.
A spokesman for the ministry, Jean-Baptiste Mattei, said the Iranian announcement was not a great surprise because the IAEA, the U.N. nuclear watchdog, had said in August that Iran was developing new nuclear capacities.
``The door to negotiations is always open, but at the same time the priority goes to the negotiations for a U.N. Security Council resolution,'' Mattei said at a news conference.
French President Jacques Chirac, meanwhile, expressed support for sanctions against Iran but insisted that they be temporary and reversible.
Russian Defense Minister Sergei Ivanov said he didn't ``share concerns'' about the launching of a second network of centrifuges, expressing confidence that the new centrifuges ``are under the complete control of the International Atomic Energy Agency, for scientific research purposes.''
He also said the centrifuges were ``completely empty, so to talk about enriched uranium or uranium for military use, is at the very least premature.''
The basis of his statement was unclear, however. The IAEA monitors both ``cascades'' of centrifuges, but they are not under its ``complete control,'' as Ivanov asserted. And _ unlike Ivanov _ the Iranian official cited by ISNA said the second network was no longer empty but enriching small amounts of uranium.
Other Russian officials also had shared previously shared the opinion of the United States and its western allies, Britain, France and Germany that even ``dry testing'' centrifuges was cause for concern.
Russia and China, which can veto Security Council resolutions and have close economic ties with Iran, are reportedly pushing for continued dialogue with Iran instead of punishment.
In a separate report on Friday, ISNA quoted Ali Larijani, Iran's top nuclear negotiator, as saying his country's enrichment program should not hinder negotiations with the West.
``It is possible to review both nuclear and regional issues through negotiation,'' Larijani was quoted as saying.
Larijani called for an open negotiation on the enrichment issue, and blamed the West of being irrational in its opposition to an Iranian nuclear program, which Tehran says is geared toward purely civilian use.
Diplomats, who spoke on condition of anonymity because they were not authorized to divulge the information to media, told The Associated Press on Monday that even the decision to ``dry test'' the 164 centrifuges in the second Iranian pilot enrichment facility showed Iran's defiance of the Security Council. The council had set an Aug. 31 deadline for Tehran to cease all experiments linked to enrichment.
Iran produced a small batch of low-enriched uranium _ suitable as nuclear fuel but not weapons grade _ in February, using its initial cascade of 164 centrifuges at its pilot plant at Natanz.
The Iran official quoted by ISNA said the nuclear watchdog was fully aware that Tehran was injecting the gas in its new centrifuges, and that nuclear inspectors had already arrived in Iran.
The Vienna, Austria-based IAEA would not comment on the report.
Iran says it plans to install 3,000 centrifuges at Natanz by the end of this year. Some 54,000 centrifuges would be required to produce enough nuclear fuel for a reactor.
Although Iran is nowhere near that goal, its successful operation of more cascades of centrifuges indicates that the country is gradually mastering the complexities of producing enriched uranium.
The U.S. and its European allies are circulating a draft U.N. Security Council resolution that would ban the sale of missile and nuclear technology to Iran and deny the country certain assistance from the U.N. nuclear watchdog.
The enrichment process takes gas produced from raw uranium and aims to increase its proportion of the uranium-235 isotope, needed for nuclear fission.
The gas is pumped into a centrifuge, which spins, causing a small portion of the heavier, more prevalent uranium-238 isotope to drop away. The gas then proceeds to other centrifuges _ thousands of them _ where the process is repeated, increasing the proportion of uranium-235.