Iran's Fordo Nuclear Complex Reaches Capacity WASHINGTON - Iran has finished installing all the critical equipment at a deep underground site where it is producing nuclear fuel that could quickly be converted to use in a nuclear weapon, international inspectors reported on Friday. But they said Iran has yet to ramp up production, leaving several months for President Obama and his allies to work on a diplomatic solution that could avoid a military confrontation. The report, by the International Atomic Energy Agency, also said that satellite photographs show Iran has worked for months to alter another site that the agency has long suspected may have been used for weapons-related experiments. Inspectors have been barred, and the agency said it fears that the movement of earth and removal of equipment has been so widespread that its ability to "conduct effective verification will have been seriously undermined." The report, which is updated and circulated quarterly to the agency's board, was published just two days after Mr. Obama told reporters at a news conference in Washington that he would try to engage Iran in new negotiations, which went nowhere in his first term. "I will try to make a push in the coming months to see if we can open up a dialogue between Iran and not just us, but the international community, to see if we can get this thing resolved," he said. Administration officials and diplomats said they believe, based on the I.A.E.A. reports and other intelligence, that it will be at least spring before Iran has amassed enough medium-enriched uranium to make a single weapon. That is the latest "red line" that Israel's prime minister, Benjamin Netanyahu, has drawn, suggesting that at that point Israel might be forced to take military action. But Mr. Netanyahu made a similar threat in the fall. The deadline slipped - as many have before - as it became clear that Iran's production rate for 20 percent enriched uranium, the type that could be converted fastest to bomb fuel, has not been as rapid as Israel and the United States had first predicted. The new report underscores that reality. The inspectors found that, as intelligence officials and diplomats reported several weeks ago, the deep underground site called Fordo, near the holy city of Qum, is virtually complete. It is filled with 2,784 centrifuges, the maximum number it was designed to hold. Of those, 644 were added since the agency's August report. But only 696 of the centrifuges are actually enriching uranium, while another 696 are very close to that stage. "They could double the rate of production at Fordo very quickly," said a European diplomat who follows the agency's work. They could go at any time. After that, officials say, it would be only a few months before Iran had enough fuel to produce a weapon if it decided to do so. However, American intelligence officials are still sticking to their conclusion, which dates back to 2007, that Iran has not made a "political decision" to produce a weapon, but may want to keep the option open. Cliff Kupchan, who follows the Iranian nuclear project for the Eurasia Group, wrote on Friday that Iran's decision to make clear that it "is poised to increase significantly its production rate of medium-enriched uranium yet has refrained from doing so" suggests it is seeking some more leverage in the next round of diplomacy. The West, and the U.S., the Iranians may calculate, will be willing to pull back on sanctions in return for stopping Iran from coming that close to being able to produce even a single weapon. Iran has diverted slightly less than 100 kilograms of its medium-enriched uranium to fuel a research reactor in Tehran that is used to produced medical isotopes. Once converted to reactor use, that fuel is very difficult to use in a weapon. Israel cited that diversion as one reason it put off the threat of attack. American officials are hoping to put together a revised offer to Iran that would forestall the moment when it had enough fuel for a single weapon. "Once again, we need to put time on the clock," said one senior administration official involved in the discussions over what kind of proposal to make. So far, Iran has rejected offers that would require it, as a first step, to halt production and to ship its existing stockpiles of fuel out of the country. William J. Broad contributed reporting from New York.