Iran's supreme leader Ayatollah Ali Khamenei has denied Western claims that Iran intends to develop nuclear arms.
"We fundamentally reject nuclear weapons and prohibit the production and the use of nuclear weapons," he said in a speech broadcast on state television.
The Iranian leader said the US knows it is "wrong" when it asserts Tehran is pursuing a covert nuclear bomb.
The US and five other countries are to hold talks with Iran shortly on a range of issues, including nuclear armaments.
The supreme leader's comments are the first official response to the United State's decision to scrap a European missile initiative, a plan put forward by the former Bush administration to counter, in part, any long-range Iranian missile threat.
"They [the US] falsely accuse the Islamic republic of producing nuclear weapons," said Ayatollah Khamenei.
"Despite friendly messages and words", the current US government was anti-Iranian, he said.
Iran has always denied assertions from the US, Israel and other European powers that it is seeking to build nuclear arms.
Tehran insists its uranium enrichment initiative is helping establish a purely peaceful civilian nuclear energy programme.
International talks with Iran are scheduled for 1 October.
The United States, Russia, the UK, France, China and Germany are set to attend.
The European Union says it expects the meeting to take place in Turkey.