What are Iran's nuclear ambitions and why are they so controversial?

At the heart of Israel's attacks on Iran is Tehran's controversial nuclear program.

Tehran says it wants to possess nuclear technology for peaceful purposes and has denied accusations by Western powers that it is seeking to develop nuclear weapons.

The International Atomic Energy Agency (IAEA), the UN nuclear watchdog, has long accused Iran of violating its non-proliferation obligations.

On Thursday - for the first time in almost 20 years - the IAEA adopted a resolution declaring that Iran was in violation of these obligations, CNN writes . 

Original agreement

US intelligence agencies and the IAEA believe Iran had a secret and coordinated nuclear weapons program that it halted in 2003. Iran denies ever having had one.

Under a 2015 nuclear deal, Iran was only allowed to enrich uranium to 3.67% purity, could maintain a uranium stockpile of 300 kg and was only allowed to use highly basic IR-1 centrifuges - machines that spin uranium gas at high speeds for enrichment purposes.

A year after US President Donald Trump withdrew the US from the deal, Iran gradually abandoned all restrictions it placed on the program and began enriching uranium to 60% purity - a short technical step away from weapons-grade levels of 90%.

US sanctions have dealt a severe blow to Iran's economy, but they have not destroyed it. Israel's assassinations of senior Iranian officials in recent years - including a prominent nuclear scientist - have also failed to curb Iran's uranium enrichment.

Iran has said its right to enrich uranium is non-negotiable.

Latest report

An IAEA report in May, seen by Reuters, found that Iran conducted covert nuclear activities with materials that had not been declared to the nuclear watchdog at three sites that have long been under investigation.

A separate IAEA report sent to member states in late May said Iran's stockpile of 60% enriched uranium had increased to 408 kg. That is enough, if further enriched, for nine nuclear weapons, according to an IAEA metric.