"Iran's position remains unchanged. Iran's nuclear activities have always been peaceful and will remain peaceful," foreign ministry spokesman Saeed Khatibzadeh told a news conference.

"The supreme leader's fatwa banning weapons of mass destruction and nuclear weapons is still valid," he added, referring to Khamenei's religious edict.

The renewed pledge came a week after Intelligence Minister Mahmoud Alavi said it would not be Tehran's fault if the country was ever "pushed" towards developing a nuclear bomb.

"Our nuclear industry is a peaceful industry. The supreme leader explicitly stated (that) in his fatwa," Alavi said in a state television interview broadcast on February 8.

"But if a cat is caught in a corner, it may behave differently... If they are pushing Iran in that direction, then it is not Iran's fault, but those who pushed it."

He stressed that "under normal circumstances, Iran has no such intention or plan".

Iranian intelligence ministers can only be appointed or dismissed with the approval of the supreme leader.

Iran had claimed the existence of the fatwa for years before making the text public for the first time in 2010, at a time of crisis over Iran's nuclear programme.

Tehran was at the time accused by the international community, especially the West and Israel, of seeking to secretly acquire the atomic bomb.

The fatwa declares the use of the atomic bomb and other weapons of mass destruction to be "haram", or forbidden by Islam, and it is regularly cited by Iranian authorities as a guarantee of Tehran's good intentions.

But the US State Department described Alavi's remarks as "very concerning" and said Iran was obliged under the Nuclear Non-Proliferation Treaty to never "acquire nuclear weapons".

This comes as a 2015 landmark deal between Iran and world powers limiting Tehran's nuclear programme in exchange for international sanctions relief is hanging by a thread.

Former US president Donald Trump withdrew from the accord in 2018 and reimposed sanctions on Tehran, with Iran a year later gradually suspending its compliance with most key nuclear commitments in response.

The new administration of President Joe Biden has expressed willingness to return to the deal, but insisted that Iran first resume full compliance while Tehran has called for the immediate lifting of sanctions.

Tasnim news agency, considered close to Iran's ultraconservatives, has blasted Alavi over his "astonishing remarks" that could have "very serious consequences".

It said in an editorial that the leader's fatwa was not designed just to "appease" the West but showed that an atomic bomb would go against "the nature of the Islamic republic".

"These remarks are completely against national interests as they can strengthen the West's leverage in negotiations and more importantly, give credence to the America's unjust" stance against Iran, Tasnim said.