Iran’s supreme leader Ali Khamenei said Wednesday the nation would never surrender as demanded by President Donald Trump and warned the United States it would face “irreparable damage” if it intervenes in support of its ally.

The speech came six days into the conflict, with Trump demanding Iran’s “unconditional surrender” while boasting the United States could kill Khamenei and fueling speculation about a possible intervention.

The long-range blitz began Friday, when Israel launched a massive bombing campaign that prompted Iran to respond with missiles and drones.

“This nation will never surrender,” Khamenei said in a speech read on state television, in which he called Trump’s ultimatum “unacceptable.”

“America should know that any military intervention will undoubtedly result in irreparable damage,” he said.

Khamenei, in power since 1989 and the final arbiter of all matters of state in Iran, had earlier vowed the country would show “no mercy” towards Israel’s leaders.

The speech followed a night of strikes, with Israeli attacks destroying two buildings making centrifuge components for Iran’s nuclear program near Tehran, according to the UN nuclear watchdog.

“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.

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.

Iran’s Islamic Revolutionary Guard Corps (IRGC) said they had launched hypersonic Fattah-1 missiles at Tel Aviv.

Hypersonic missiles travel at more than five times the speed of sound and can manoeuvre mid-flight, making them harder to track and intercept.

No missile struck Tel Aviv overnight, though AFP photos showed Israel’s air defence systems activated to intercept missiles over the commercial hub.

Iran also sent a “swarm of drones” towards Israel, while the Israeli military said it had intercepted a total of 10 drones launched from Iran.

It said one of its own drones had been shot down over Iran.

Trump fueled speculation about US intervention when he made a hasty exit from the G7 summit in Canada, where the leaders of the club of wealthy democracies called for de-escalation but backed Israel’s “right to defend itself.”

He boasted that the United States could easily assassinate Khamenei.

“We know exactly where the so-called ‘Supreme Leader’ is hiding. He is an easy target, but is safe there -- We are not going to take him out (kill!), at least not for now,” Trump wrote on his Truth Social platform.

Trump met with his National Security Council to discuss the conflict. There was no immediate public statement after the hour and 20 minute meeting.

US officials stressed Trump has not yet made a decision about any intervention.