Nuclear threat, concerns over missile development: What prompted US to attack Iran?

The strikes on Iran were launched after diplomatic negotiations between Washington and Tehran over the nuclear issue collapsed without producing an agreement.

• US and Israel launched major strikes on Iran, killing Khamenei
• Trump cited Iran's nuclear, missile threats, and protest crackdowns.
• Iran retaliated with attacks across the Middle East after strikes

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The US, in coordination with Israel, carried out sweeping military strikes against Iran early Saturday (February 28) in what officials described as the most far-reaching assault on the country in decades.

The operation — named 'Epic Fury' by Washington and 'Lion’s Roar' by Israel — resulted in the death of Iran’s Supreme Leader Ali Khamenei on Sunday, as announced by both governments and later confirmed by Iranian state media.

The decision marked the most consequential foreign policy move of US President Donald Trump’s tenure. Though he had campaigned for re-election portraying himself as a leader committed to avoiding new wars and favoring diplomacy, Trump said the strikes became necessary after negotiations with Tehran over its nuclear activities collapsed just days earlier without agreement.

Nuclear program at the centre

At the heart of the US administration’s rationale was the claim that Iran was advancing toward the capability to build a nuclear weapon. Trump insisted repeatedly that Tehran must never be allowed to obtain such arms. While he had previously declared that American airstrikes last June had destroyed Iran’s atomic infrastructure, he alleged this week that Iranian authorities had resumed work on the program.

US and Israeli officials argued that Iran’s uranium enrichment had reached levels far beyond what would be required for civilian energy production. Western governments have long maintained that there is no peaceful justification for enrichment at such high concentrations.

The United Nations’ nuclear watchdog has expressed alarm over the scale of Iran’s activities, noting that no country has enriched uranium to similar levels without ultimately producing nuclear weapons.

Iran has consistently denied seeking a bomb, asserting that as a signatory to the Non-Proliferation Treaty, it has the right to enrich uranium for civilian use. US intelligence agencies and international inspectors previously assessed that Iran halted a structured weapons program in 2003.

However, the Trump administration argued that Tehran’s renewed activity and the breakdown of talks left military action as the only remaining option to prevent nuclear escalation.

Concerns over missile development

Beyond nuclear issues, Trump pointed to Iran’s expanding missile program as a growing security threat. In remarks made following the strikes on Iran, he claimed Tehran was developing long-range missile systems capable of targeting European allies, American troops stationed abroad, and potentially the US mainland in the near future.

The US administration portrayed the combination of advanced missiles and potential nuclear capability as an unacceptable risk. The administration said Saturday’s strikes were intended to remove what it called imminent threats to American citizens, troops, and allies worldwide.

Response to domestic crackdown

Another factor cited by Trump was Iran’s handling of domestic unrest. He accused Iranian authorities of killing tens of thousands of demonstrators during recent protests fueled by economic hardship.

Earlier this year, Trump had pledged to respond if Iranian security forces violently suppressed civilian protests. The latest action, officials suggested, was consistent with that commitment.

Regime change call

In addition to outlining security concerns, Trump openly encouraged Iranians to remove their ruling clerical leadership. Addressing the Iranian public, he urged citizens to seize what he described as a rare opportunity to claim control of their country’s future. He warned that air operations would continue for as long as necessary to achieve what he characterized as lasting peace in the Middle East.

Israeli Prime Minister Benjamin Netanyahu said earlier that Khamenei’s compound had been destroyed, and a senior Israeli official reported his body had been recovered, before Iranian media confirmed his death.

Retaliation and regional fallout

Iran’s foreign minister condemned the assault as illegal and unprovoked. Within hours, Tehran launched retaliatory attacks across the Middle East. The escalation follows last year’s 12-day conflict between Israel and Iran, which ended in a ceasefire after U.S. strikes targeted Iranian nuclear sites.

In sum, the United States said it attacked Iran to block what it viewed as an accelerating nuclear threat, curb missile development, counter long-standing hostilities toward American forces and allies, respond to Tehran’s domestic repression, and potentially open the door to political change inside the country. The move represents one of the most dramatic escalations in US–Iran tensions in decades, with far-reaching implications for regional and global stability.