Travel in the Middle East and around the world has been disrupted as several key transit hubs close their airports, and major airlines cancel flights.

Smartraveller has also updated its overall advice level to several countries in the region.

Go here for the full list: smartraveller.gov.au/destinations

Read more about the disruptions in this story from Doug Dingwall:

Jonathan Panikoff of the Middle East Security Initiative at the Atlantic Council says the future of Iran's leadership is uncertain amid ongoing US–Israel strikes, with multiple possible scenarios emerging.

Panikoff says one baseline scenario is that the Islamic Revolutionary Guard Corps (IRGC) could take control, maintaining the existing power structure. 

More ambitious regime-change scenarios — where security services stand aside or switch allegiance, similar to the 1979 revolution — are considered less likely.

"You may now have hardliners within the regime coming together to institute almost a military-like model ... where power is ultimately held within the military, not the religious leadership," Panikoff said.

Speaking at the emergency Security Council meeting, UN Secretary-General António Guterres says the situation on the ground in Iran is "very fluid".

He says the US–Israeli strikes reportedly affected around 20 cities, including Tehran, Ham, Qom and Mashhad, with explosions near government compounds, including the presidential palace.

Regarding Israeli claims that Iranian Supreme Leader Ayatollah Ali Khamenei was killed, Guterres says he is "not in a position to confirm".

US President Donald Trump has used social media to declare that Iran's supreme leader, Ayatollah Ali Khamenei, is dead.

He wrote on Truth Social:

Khamenei, one of the most evil people in History, is dead. 

This is not only Justice for the people of Iran, but for all Great Americans, and those people from many Countries throughout the World, that have been killed or mutilated by Khamenei and his gang of bloodthirsty THUGS. 

He was unable to avoid our Intelligence and Highly Sophisticated Tracking Systems and, working closely with Israel, there was not a thing he, or the other leaders that have been killed along with him, could do.

This is the single greatest chance for the Iranian people to take back their Country. 

We are hearing that many of their IRGC, Military, and other Security and Police Forces, no longer want to fight, and are looking for Immunity from us. 

As I said last night, “Now they can have Immunity, later they only get Death!” 

Hopefully, the IRGC and Police will peacefully merge with the Iranian Patriots, and work together as a unit to bring back the Country to the Greatness it deserves.

That process should soon be starting in that, not only the death of Khamenei but the Country has been, in only one day, very much destroyed and, even, obliterated. 

The heavy and pinpoint bombing, however, will continue, uninterrupted throughout the week or, as long as necessary to achieve our objective of PEACE THROUGHOUT THE MIDDLE EAST AND, INDEED, THE WORLD!

UN Secretary-General António Guterres is speaking at an emergency Security Council meeting, urging immediate de-escalation in the region.

"Since this morning I have condemned the massive military strikes by the United States and Israel against Iran. And I also condemn the subsequent attacks by Iran, violating the sovereignty and territorial integrity of Iraq, Qatar, Saudi Arabia and the United Arab Emirates," he says.

Guterres warns the situation represents a "grave threat to international peace and security", saying that military action "carries the risk of igniting a chain of events that no-one can control" in the region.

"Let me be clear. There is no viable alternative to the peaceful settlement of international disputes. Lasting peace can only be achieved through peaceful means, including genuine dialogue and negotiations."

Virgin Australia confirms four flights bound for Qatar were turned back overnight.

• VA1 (Sydney to Doha)
• VA15 (Brisbane to Doha)
• VA7 (Melbourne to Doha)
• VA21 (Perth to Doha)

Flights that have left Doha for Australia were continuing as scheduled, a Virgin spokesperson said.

"The safety of our guests and crew is always our top priority," the spokesperson said.

"Guests booked to travel to Doha in the coming days should closely monitor their flight information and visit the Smartraveller website for the latest travel advice."

It is just after 4pm in New York where an emergency meeting of the UN Security Council is taking place. 

Russia's UN mission said Russia and China requested the meeting "in connection with the unprovoked act of armed aggression by the United States and Israel against the Islamic Republic of Iran".

The session was also called for by France, Bahrain and Colombia.

"During the Security Council meeting, we will demand from the United States and Israel to immediately cease their illegal and escalatory actions and embark on a path toward a political and diplomatic settlement," the Russian statement said.

A UN diplomat said Secretary-General António Guterres plans to speak at the session. 

Earlier on Saturday, Guterres condemned the escalation in the Middle East.

He warned that the "use of force by the United States and Israel against Iran, and the subsequent retaliation by Iran across the region, undermine international peace and security".

Of the Western leaders who have responded to the attacks on Iran, Anthony Albanese has offered the US some of the most enthusiastic support.

In a lengthy post on X last night, the prime minister said:

"We support the United States acting to prevent Iran from obtaining a nuclear weapon and to prevent Iran continuing to threaten international peace and security."

Canadian Prime Minister Mark Carney was similarly supportive of the US-Israeli action, and used very similar words:

"Canada supports the United States acting to prevent Iran from obtaining a nuclear weapon and to prevent its regime from threatening international peace and security."

Many European leaders were more cautious, urging restraint and calling for diplomatic talks to resume.

British Prime Minister Sir Keir Starmer called for a "return to the diplomatic process".

French President Emmanuel Macron said the "ongoing escalation is dangerous for all. It must stop".

Spanish Prime Minister Pedro Sánchez criticised the strikes:

"We reject the unilateral military action by the United States and Israel, which represents an escalation and contributes to a more uncertain and hostile international order."

US President Donald Trump has told NBC he believes Iran's Supreme Leader, Ayatollah Ali Khamenei, has died.

Asked when he would receive confirmation about Khamenei's status, Trump said:

"I've spoken to a lot of people beyond, and we feel certain, we feel, we feel that that is a correct story."

"The people that make all the decisions, most of them are gone," he said, adding that "a large amount of leadership" in Iran was also killed, although he declined to go into more details.