"The idea of continuing to develop a nuclear bomb still beats in their hearts. We bear responsibility to ensure that the nuclear project, which has been gravely damaged, in close cooperation with the Americans, will never be activated," David Barnea said at an award ceremony for Mossad agents in Jerusalem.

The outgoing spy chief, who will end his term in June 2026, praised Israel's surprise opening strikes of the war, which he suggested revealed the vast amount of intelligence Israeli spies had collected on Iran.

"The ayatollahs' regime awoke, in a single moment, to discover that Iran is entirely exposed and penetrated," Barnea said.

Expressing his scepticism towards any diplomatic solution with Tehran, Barnea added: "Iran believes it can deceive the world once again and implement yet another bad nuclear deal. We did not and will not allow a bad deal to be realised."

Western powers have long accused Iran of seeking nuclear weapons and sought to prevent it acquiring them, while Tehran has always denied the accusations.

In his first term, US President Donald Trump withdrew from a landmark deal limiting Iran's enrichment of nuclear material in exchange for sanctions relief.

Israel had opposed the deal, signed in 2015.

Iran and the United States began negotiations for a new agreement in April, mediated by Oman, but those talks were brought to an abrupt halt by Israel's surprise attack on Iran on June 13, which triggered the 12-day conflict.

The US joined in with its own strikes on three Iranian nuclear facilities.

Trump has repeatedly said his country's attack obliterated Iran's nuclear programme, but the full extent of the damage remains unknown.

The Pentagon has said the strikes delayed Iran's nuclear programme by between one and two years, contradicting an initial classified US intelligence report that, according to American media, found the setback was only a few months.

Iranian supreme leader Ayatollah Ali Khamenei has previously rebuffed Trump's claims that Iran's nuclear programme had been destroyed, telling him to "keep dreaming".