Israel's strikes on Iran have taken aim at its nuclear facilities, amid fears that the Islamic republic is seeking to develop nuclear weapons -- an accusation Tehran denies.

Experts told AFP that while the attacks might have caused some damage to Iran's nuclear programme, they are unlikely to have delivered a fatal blow.

- What is the extent of the damage? -

Israel targeted Iran's air defence capabilities on Saturday, pressing on with a massive wave of strikes it began a day earlier that targeted Iranian nuclear and military facilities, prompting counterattacks by Iran.

Israeli Prime Minister Benjamin Netanyahu vowed to hit "every target of the ayatollah regime", adding: "What they have felt so far is nothing."

Iranian President Masoud Pezeshkian, meanwhile, warned the continued "aggression will be met with a more severe and powerful response".

Russian President Vladimir Putin told his US counterpart Donald Trump Saturday that Moscow was ready to hold a fresh round of peace talks with Kyiv after June 22, once the sides complete exchanging prisoners and soldiers' bodies.

Ukraine's leader Volodymyr Zelensky meanwhile did not mention whether Ukraine would agree to the next round of talks, only saying that "the exchanges will be completed and the parties will discuss the next step."

Iranians and Israelis woke to smoke and rubble on Sunday after the arch-rivals expanded their attacks overnight, with Israel striking Tehran's defence ministry, and Iran unleashing a deadly barrage of missiles.

Air raid sirens and explosions were heard by AFP journalists in Jerusalem and Tel Aviv early Sunday, as Israel's military said millions of Israelis were "running for shelter" around the country.

Israel's emergency services said at least eight people, including children, were killed in the overnight strikes, and around 200 were wounded.

Pro-Palestinian student protest leader Mahmoud Khalil remained in US detention Friday despite an expected release, his lawyer said, following reported accusations of inaccuracies in his permanent residency application.

US District Judge Michael Fabiarz had issued an order Wednesday that the government could not detain or deport Khalil, a legal permanent resident, based on Secretary of State Marco Rubio's assertions that his presence on US soil posed a national security threat.

The order gave the government until Friday to release Khalil.

An Afghan man pleaded guilty on Friday to plotting to carry out an attack on US election day on behalf of the Islamic State (IS) group, the Justice Department said.

Nasir Ahmad Tawhedi, 27, was arrested in the central US state of Oklahoma in October, several weeks before the November 5 presidential election.

He pleaded guilty in a federal court in Oklahoma City to charges of conspiring to provide material support to IS and attempting to receive firearms and ammunition to carry out an attack.

The son of Iran's late shah appealed Friday to the country's security forces to abandon the cleric-run state, voicing hope for toppling the Islamic republic after Israel launched military strikes.

Reza Pahlavi blamed Supreme Leader Ayatollah Ali Khamenei for having "dragged Iran into a war" with Israel and described the government in Tehran as "weak and divided."

"It could fall. As I have told my compatriots: Iran is yours and yours to reclaim. I am with you. Stay strong and we will win," he said in a statement.

Israel's firefighting service said its teams were responding to several "major" incidents resulting from an Iranian missile attack, including efforts to rescue people trapped in a high-rise building.

"Firefighting crews are handling several major incidents, mainly in the Dan region" around Tel Aviv, a statement said, adding that "firefighters are working in a high-rise building to rescue trapped individuals and extinguish a fire, as well as responding to two additional destruction sites."

For President Donald Trump, few goals on the world stage have been more explicit -- he will not drag the United States into another "forever war."

Yet Israel's massive strikes on Iran will test that promise as never before, potentially setting up a showdown with his base as Trump decides how much support the United States will offer.

Trump had publicly called for Israel not to strike as he sought a negotiated solution, and his roving envoy Steve Witkoff had been scheduled to meet Iranian officials for the sixth time Sunday.

Israeli Prime Minister Benjamin Netanyahu's nearly 20-year-old threat to strike Iran came true on Friday, as US President Donald Trump warned Tehran of further "brutal" attacks if it refuses to negotiate.

In its largest military action against Iran to date, Israel's strikes hit about 100 targets including nuclear facilities and military command centres, and killed the armed forces' chief, top nuclear scientists and other senior figures.