Iran accused the US on Friday of using "forged documents" and relying on subterfuge to make its case that Teheran is trying to build a nuclear weapon, according to a confidential letter obtained by The Associated Press. The eight-page letter, written by Iran's chief envoy to the UN nuclear agency in Vienna, denounces Washington's allegations against the Islamic republic as "fabricated, baseless and false." The letter does not specify what documents Iran is alleging were forged. It also lashes out at Britain and France for "ill will and political motivation" in their dealings on Iran. Iranian envoy Ali Asghar Soltanieh sent the letter to Mohamed ElBaradei, the head of the International Atomic Energy Agency, whose 35-nation board will take a hard new look at Iran's nuclear program next week. Iran insists its nuclear activities are peaceful and geared solely toward generating electricity. The US and key allies contend the Islamic republic is covertly trying to build an atomic bomb. Teheran has bristled at the agency's latest report, which accuses Iran of defiantly continuing to enrich uranium and refusing to clear up lingering questions about possible military dimensions to its nuclear program. In the letter, a copy of which was obtained by the AP, Soltanieh insists that Iran has demonstrated "the full commitment of my country to its obligations" under an IAEA nuclear safeguards agreement. But it takes sharp aim at Washington for giving the UN nuclear watchdog unspecified intelligence and other evidence allegedly recovered from a laptop computer that reportedly was smuggled out of Iran. US intelligence later assessed the information as indicating that Teheran had been working on details of nuclear weapons, including missile trajectories and ideal altitudes for exploding warheads. The material on the laptop also included videos of what intelligence officials believe were secret nuclear laboratories in Iran. "By interfering in the work of the IAEA and exerting various political pressures, the government of the United States attempted to spoil the cooperative spirit between the Islamic republic of Iran and the IAEA," the letter reads. "The government of the United States has not handed over original documents to the agency since it does not in fact have any authenticated document and all it has are forged documents," Soltanieh said. "The agency didn't deliver any original documents to Iran and none of the documents and materials that were shown to Iran have authenticity and all proved to be fabricated, baseless allegations and false attributions to Iran," he added. "Therefore, this subject must be closed," Soltanieh wrote. State Department spokesman Ian Kelly declined to comment on Iran's allegations. "We are still awaiting a meaningful response to the P5+1 offer from last April, and to our offer of engagement," Kelly said, referring to the group of world powers trying to craft a diplomatic resolution to the standoff. The group includes the five permanent members of the Security Council - Britain, China, France, Russia and the United States - plus Germany. "We have provided a path whereby Iran can become a full and respected member of the international community," Kelly said. "It is up to Iran to make a decision as to whether it chooses that path." Officials at the French Foreign Ministry would not immediately comment. France has been increasingly vocal in criticizing Iran's nuclear program under President Nicolas Sarkozy, who recently said Iranians didn't "deserve" leaders like theirs. Sarkozy has been in the forefront of the push for new, stronger sanctions. A spokeswoman for Britain's Foreign Office denied the allegations in Soltanieh's letter. She said Britain had consistently sought a way to "give diplomacy a chance to succeed." "I would deny any suggestion of ill-will in the strongest possible terms," she said, speaking anonymously in line with department policy. "We would have no hesitation in saying that absolutely the reverse is true." The IAEA itself has pressed the US and other governments to share more details on Iran-related intelligence. In its latest report on Iran, the UN agency noted that "constraints placed by some member states on the availability of information to Iran are making it more difficult for the agency to conduct detailed discussions with Iran." In a brief telephone interview Friday evening, Soltanieh told the AP he hoped the letter would pressure the US to fully divulge the source of any intelligence implicating Iran. "We are the victims of negligence, because people still don't know what this is all about," he said. The nuclear agency's latest assessment did acknowledge that Iran has been producing nuclear fuel at a slower rate and has allowed UN inspectors broader access to its main nuclear complex in the southern city of Natanz and to a reactor in Arak. But it cautions that there are "a number of outstanding issues which give rise to concerns and which need to be clarified to exclude the existence of possible military dimensions." The report, to be examined next week, has raised the specter of harsher international sanctions against Iran for not answering lingering questions about its nuclear activities. Senior UN officials have said Iran has been feeding uranium ore into some of its 8,300 centrifuges at a reduced rate, suggesting that sanctions already in place may be hampering its program. As of August 12, only about 4,600 of those centrifuges were actively enriching uranium, compared with about 4,900 in June - the last time the nuclear agency issued a report on Iran's nuclear activities - officials said. Since then, they said, Iran has installed roughly 1,000 more centrifuges, but it appeared that many were idle. Soltanieh's letter contends the overall assessment on Iran is positive. But he says concerns raised by the US and others have "totally overshadowed and undermined" the steps that Iran has taken to comply with IAEA demands for transparency. US President Barack Obama has given Iran something of an ultimatum: Stop enriching uranium - which, if done at a high level, can produce fissile material for the core of a nuclear weapon - or face harsher penalties. In exchange for stopping, it could get trade benefits from the P5+1 countries.