BERLIN -- Iran has answered more questions about the history of its nuclear program but is restricting access to its nuclear work and expanding its enrichment of uranium in defiance of the Security Council, a United Nations watchdog agency reported yesterday.
The International Atomic Energy Agency said Iran has not provided "full transparency" about its current activities and now has nearly 3,000 operating centrifuges - the number required to produce enough enriched uranium in one year for a nuclear weapon.
The report, distributed yesterday to member states of the IAEA, could be a turning point in the confrontation over Iran's nuclear program, which the Bush administration alleges is aimed at developing a weapon.
The United States pledged to move ahead with an effort to impose further economic sanctions against Iran. Other countries, notably China and Russia, oppose that course of action, and are expected to argue that the report represents progress in uncovering Iran's nuclear secrets.
One IAEA official said judgments about the report, completing a two-month process launched by IAEA chief Mohamed ElBaradei despite criticism from the United States, are "clearly a matter of perspective: The glass is both half-full and half-empty."
White House spokeswoman Dana Perino said the United States will work with the U.N. Security Council toward a third set of sanctions against Iran.
"This report sadly makes clear that Iran seems uninterested in working with the rest of the world," she said.
U.S. officials largely dismissed the report that Iran has cooperated in clearing up uncertainties about the history of its nuclear development, focusing instead on the report's acknowledgment that Iran is continuing to enrich uranium in defiance of Security Council demands.
State Department spokesman Sean McCormack attempted to highlight the report's warning that the IAEA's knowledge of Iran's current nuclear activities is dwindling. The United States is trying to schedule a meeting with senior envoys from Britain, China, France, Germany and France to discuss a new U.N. sanctions resolution, McCormack said.
But the report might have dimmed prospects for further sanctions, and the Bush administration pointed the finger yesterday at China.
"There has been a dragging of feet by the Chinese ... to come to an agreement on a new resolution as quickly as possible," said Zalmay Khalilzad, the U.S. ambassador to the United Nations.
Britain took a slightly less negative tack, saying that the report would be studied carefully.
U.N. officials close to the investigation, who could not be named because they were not authorized to speak, said they were baffled by the reaction from the United States, Britain and France, calling the report an indication of "substantial progress in only two months. Iran has clearly changed gears as far as explaining their activities."
However, the report also notes that Iran now has 2,952 operational enrichment centrifuges in 18 linked cascades. The report notes that in the past year, Iran has fed 2,700 pounds of uranium gas (UF6) into the cascades, less than the expected capacity of the system. The IAEA said that, as of Nov. 5, Iran had produced 266 tons of UF6, all of which remains under IAEA supervision.
The report says that while Iran reports having enriched uranium-235 to 4.8 percent - far below the 90 percent enrichment needed for weapons-grade uranium, but enough for power generation - inspectors could find no evidence of anything beyond 4 percent U-235.