The UN nuclear watchdog said Israeli strikes on Wednesday destroyed two buildings making centrifuge components for Iran's nuclear program near Tehran, while Iran said it fired hypersonic missiles as the arch foes traded fire for a sixth day.
Hours after US President Donald Trump demanded Iran's surrender, supreme leader Ali Khamenei vowed his country would show "no mercy" towards Israel's leadership.
Khamenei, in power since 1989 and the final arbiter of all matters of state in Iran, was to deliver a televised speech Wednesday.
Trump insists the United States has played no part in ally Israel's bombing campaign, but also warned his patience was wearing thin.
The long-range blitz began Friday, when Israel launched a massive bombing campaign that prompted Iran to respond with missiles and drones.
After the Israeli military issued a warning for civilians to leave one district of Tehran for their safety, Israeli warplanes hit the capital early Wednesday.
"More than 50 Israeli Air Force fighter jets... carried out a series of air strikes in the Tehran area over the past few hours," the Israeli military said, adding that several weapons manufacturing facilities were hit.
"As part of the broad effort to disrupt Iran's nuclear weapons development program, a centrifuge production facility in Tehran was targeted."
Centrifuges are vital for uranium enrichment, the sensitive process that can produce fuel for reactors or, in highly extended form, the core of a nuclear warhead.
The strikes destroyed two buildings making centrifuge components for Iran's nuclear program in Karaj, a satellite city of Tehran, the International Atomic Energy Agency said Wednesday.
In another strike on a site in Tehran, "one building was hit where advanced centrifuge rotors were manufactured and tested", the agency added in a post on X.
After a prolonged shadow war, Israel said its surprise air campaign was aimed at preventing Iran from acquiring nuclear weapons -- an ambition Tehran denies.
The UN nuclear watchdog said there appeared to have been "direct impacts on the underground enrichment halls" at Iran's Natanz facility.
Israel has maintained ambiguity regarding its own atomic activities, but the Stockholm International Peace Research Institute (SIPRI) says it has 90 nuclear warheads.
The conflict derailed a running series of nuclear talks between Tehran and Washington, with Iran saying after the start of Israel's campaign that it would not negotiate with the United States while under attack.
French President Emmanuel Macron said Trump had a critical role to play in restarting diplomacy with Iran, where any attempts at "regime change" would bring "chaos".
