An Iranian missile destroyed a building in the Arab-Israeli city of Tamra
An Iranian missile destroyed a building in the Arab-Israeli city of Tamra AFP

Israel and Iran exchanged fire again on Wednesday, the sixth day of strikes in their most intense confrontation in history, fuelling fears of a drawn-out conflict that could engulf the Middle East.

Here are the latest developments:

Israeli Defence Minister Israel Katz said Wednesday that air force jets had destroyed Iran's "internal security headquarters" after the army announced it was striking military targets in Tehran.

AFP journalists reported hearing blasts in the north and east of the Iranian capital.

"Air Force jets have just destroyed the internal security headquarters of the Iranian regime -- the main arm of repression of the Iranian dictator," Katz said in a statement, vowing to "strike symbols of governance and hit the Ayatollah regime wherever it may be".

Supreme leader Ayatollah Ali Khamenei said his nation would "never surrender", while warning Israel ally the United States it would suffer "irreparable damage" if it intervenes in the conflict.

"This nation will never surrender," Khamenei said in a speech read on state television. "America should know that any military intervention will undoubtedly result in irreparable damage."

US President Donald Trump had stepped up his rhetoric, saying on Tuesday that the United States knows where Khamenei is located but will not kill him "for now".

In another post, Trump also appeared to demand Iran's "UNCONDITIONAL SURRENDER!" as he fuelled speculation over whether the United States would join Israel's attacks.

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

The Israeli military said it targeted a centrifuge facility in overnight strikes on Tehran.

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 UN nuclear watchdog later said two centrifuge production facilities had been destroyed at Karaj, just outside Tehran.

Israel's attacks have hit nuclear and military facilities around Iran, as well as residential areas.

Residential areas in Israel have also been hit, and foreign governments have scrambled to evacuate their citizens from both countries.

Israeli Prime Minister Benjamin Netanyahu's office said on Monday that at least 24 people have been killed in Israel and hundreds wounded since Iran's retaliatory strikes began Friday.

Iran said on Sunday that Israeli strikes had killed at least 224 people, including military commanders, nuclear scientists and civilians.

Israeli Foreign Minister Gideon Saar said that "regime change is not an objective of this war -- it can be a result, but it's not an objective".

French President Emmanuel Macron warned that any attempt to change the government in Iran would result in "chaos".

German Chancellor Friedrich Merz expressed support for the campaign Tuesday, saying in an interview that "this is the dirty work Israel is doing for all of us" against Iran's "mullah regime".

Iran said Wednesday it had detained five suspected agents of Israel's Mossad intelligence agency on charges of tarnishing the country's image online, Iranian news agencies reported.

"These mercenaries sought to sow fear among the public and tarnish the image of the sacred system of the Islamic Republic of Iran through their calculated activities online," the Tasnim and ISNA news agencies quoted a statement from the Revolutionary Guards as saying.

Iran announced last week that it was placing temporary restrictions on the internet for the duration of the conflict. Numerous sites and apps have since been at least partially inaccessible.

The authorities appealed to the public on Tuesday to "minimise their use of equipment connected to the internet and to take appropriate precautions" online.

State television appealed to Iranians on Tuesday to delete WhatsApp from their phones, charging that the messaging app gathers users' location and personal data and "communicates them to the Zionist enemy".

A WhatsApp spokesperson hit back against the claims, saying: "We're concerned these false reports will be an excuse for our services to be blocked at a time when people need them the most."