After weeks of conflicting responses, Iran abruptly said Saturday that it is ready to exchange uranium for nuclear fuel _ the key demand of a U.N.-sponsored initiative to defuse global fears over its nuclear program.
The conditions laid out in comments from Iran's foreign minister, however, are unlikely to satisfy the U.S. and its allies as they prepare to discuss new sanctions against Tehran at a meeting that could take place in the coming week.
Iran's stockpile of uranium is at the heart of international concerns because it offers Iran a possible pathway to nuclear weapons production if it is enriched to higher levels. Tehran insists it only wants to use the material to produce fuel for power plants and for other peaceful purposes.
Under a U.N. plan proposed in October and being pushed by Washington and five other world powers, Iran would ship most of its uranium _ up to 2,600 pounds (1,200 kilograms) of it _ abroad. It would then be enriched to higher levels in Russia, turned into fuel rods in France and returned to power a research reactor in Tehran that produces medical isotopes.
The material in the fuel rods cannot be enriched to higher levels, denying Iran the ability to use it to make weapons.
"We accepted the proposal in principle," Foreign Minister Manochehr Mottaki told reporters at a regional security conference in Bahrain.
In what is almost certain to be a deal breaker, however, he spoke of exchanging the material in phases rather than all at once as is called for in the U.N. plan. He said Iran had offered to make a first shipment of 880 pounds (400 kilograms) of enriched uranium.
Carrying it out in slow stages would leave Iran in control of enough uranium to make a bomb.
A senior Obama administration official said Mottaki's remarks appeared to fall short of demands.
"Iran's proposal today does not appear to be consistent with the fair and balanced draft agreement proposed by the IAEA in consultation with the United States, Russia, and France," the official said, speaking on condition of anonymity because the U.S. has yet to formulate an official response to the development.
Officials at the U.N. nuclear agency could not be reached for comment Saturday.
In another change to the plan, Iran wants to receive the fuel rods immediately in simultaneous exchanges for its uranium because it says it is worried that France or Russia could renege on the deal.
Another unanswered question is whether the uranium Iran is offering to exchange would actually be shipped out of the country or just left _ perhaps under observation _ inside its borders in what would present another departure from the U.N. plan.
Mottaki suggested the exchanges take place on Iran's Kish island, in the Persian Gulf, but he did not clarify whether the uranium would leave Iranian soil.
"We gave a clear answer and we responded, and our answer was we accepted in principle but there were differences in the mechanism," he said Saturday, speaking through a translator.
Further confusing matters, as of a few days ago, the U.N.'s nuclear agency had yet to receive a concrete Iranian counterproposal _ or a response of any kind _ to its initiative.
Mottaki's remarks, in which he insisted a response had been sent, were part of a string of conflicting Iranian statements that began with initial word in October that the country would accept the proposal as is. Several Iranian lawmakers later rejected the plan outright.
Some 33 to 66 pounds (15 to 30 kilograms) of uranium enriched to levels above 90 percent would be needed to produce a nuclear bomb. Iran has about 3,300 pounds (1,500 kilograms) of 3.5 percent, or low-enriched uranium _ enough to produce highly enriched material for two such weapons.
Last month, the 35-nation board of the U.N.'s International Atomic Energy Agency endorsed a resolution from the six powers _ the U.S., Russia, China, Britain, France and Germany _ criticizing Iran for defying a U.N. Security Council ban on uranium enrichment and continuing to expand its operations.
It also censured Iran for secretly building a second enrichment facility and demanded that it immediately suspend further construction on it.
British Prime Minister Gordon Brown said last month that the U.N. offer has been "comprehensively rejected" by Iran. A diplomat from one of the six powers said Wednesday that America's Western allies were waiting for Washington to formally declare the wait for an Iranian response over, probably by the end of this month.
The six countries are expected to meet next week to discuss what action to take over Iran.
EU leaders said they would support further U.N. sanctions unless Tehran starts cooperating over its nuclear program.
Associated Press Writer Matthew Lee in Washington contributed to this report.