Iran's supreme leader said Sunday that US officials know they are wrongly accusing Iran of seeking to develop nuclear weapons. In Iran's first official reaction to the US decision to scrap a European missile intercept system to defend against threats from Iran, Ayatollah Ali Khamenei claimed US President Barack Obama's administration is following the same policies as its predecessor. "The US officials who talk about Iranian missiles and their danger while saying Iran intends to build a nuclear bomb, they know these words are wrong," Khamenei said in remarks broadcast on state-run radio. "Despite its apparent friendly messages and words" the Obama administration is pursuing the same policy of Iran-phobia, he said. The US administration has invited Iran to start a dialogue on its nuclear program and gave a vague September deadline for Teheran to take up the offer. The US and five other world powers accepted an offer from Iran earlier this month to hold "comprehensive, all-encompassing and constructive" talks on a range of security issues, including global nuclear disarmament. European Union foreign policy chief Javier Solana will meet Iran's nuclear negotiator Saeed Jalili on October 1 for talks on Iran's nuclear program. Iran has long maintained the program is purely for peaceful purposes and Khamenei reiterated that Iran considers the production and use of nuclear arms forbidden by the country's Muslim beliefs. The Obama administration announced earlier this month it was scrapping a Bush-era plan for a missile defense system based in Poland and the Czech Republic. Former US president George W. Bush contended the system was needed to shoot down any Iranian missile if Teheran ever developed one with adequate range to threaten the United States or Europe. US officials have said the decision was based largely on a new US intelligence assessment that Iran's effort to build a nuclear-capable long-range missile would take three years to five years longer than originally thought. The scrapped plan will be replaced by a new one initially geared more to the threat of short- and medium-range missiles from Iran. Khamenei also addressed Iran's domestic political crisis, warning government supporters against accusing opposition members of wrongdoing without proof. It was the latest indication that the Islamic government may be easing up on critics of the June presidential election. In a speech marking the end of the Muslim holy month of Ramadan, Khamenei appeared to be working to iron out tensions that have created the country's biggest domestic political crisis since the 1979 Islamic Revolution - the fallout from the disputed June 12 election in which Iranian President Mahmoud Ahmadinejad won re-election in a race critics say was marred by widespread fraud. Amid mass trials of supporters of reformist presidential candidate Mir Hossein Mousavi, as well as claims of abuse, coerced confessions and intimidation by security forces targeting the opposition, Khamenei said while a suspect's own confession was admissible, his testimony or accusations could not be used to implicate others in the unrest. "We do not have the right to accuse without any proof," Khamenei said, urging the judiciary and security forces to pursue offenders within the bounds of the law. The speech was carried live on Iran's state radio and television. "What a suspect says in court against a third party has no legitimate validity," he said. Khamenei did not single out any individuals, but his remarks appeared to refer to testimony by some detainees who maintain that former Iranian president Hashemi Rafsanjani and other reformists supported Mousavi to weaken Khamenei. Rafsanjani - who has been absent from several recent official ceremonies, including a Friday prayer led by the supreme leader earlier in September - was seen sitting in the first row of worshippers during the prayer ceremony at which Khamenei spoke. Khamenei has been a staunch supporter of Ahmadinejad, support that has further angered critics and opened up a wide rift between the country's influential clerics - reformists on one side, hard-liners on the other. But in what could be an attempt to bridge that gap, he said accusing others in the media without any proof would create a climate of suspicion. The country has already been faced with just such a situation for months since tens of thousands took to the streets in protests after the elections, sparking a harsh government crackdown in which hundreds were arrested or detained and dozens subsequently being brought to court in mass trials. Some opposition members say 72 died in the post-vote police crackdown, roughly double the government's official casualty figures. Khamenei's latest comments could signal a change in the direction of the ongoing court cases against protesters. Some detainees blamed opposition figures and their supporters of fomenting the postelection unrest. Among those blamed were Rafsanjani and his son.