Live updates: Iran air defences activated amid reports of Israeli strike ...

University of Melbourne Political Sciences lecturer Dara Conduit has told ABC News Channel the way that Israel and Iran are responding speaks to the severity of the situation.

"The government in Israel and the regime in Iran are both in difficult positions domestically and they both have a really strong need to show to a domestic audience that they are responding to this," she said.

"Israel, [Prime Minister Benjamin] Netanyahu in particular, needed to do this. Domestically he is in a really tight spot and he is very keen to show strength and also to highlight the regional risks that Israel faces"

Dr Conduit said how Iran was reacting was important with it trying to diminish the reports.

"There is a chance that Iranian officials, particularly the Islamic Revolutionary Guard Corps will decide we can't accept this and we do need to respond and that is where there is a risk of miscalculation and a risk of mistakes and that is the scary part." she said.

Dr Conduit said she believed both sides were aware that there would not be "any winners of a direct conflict between the two states".

This is not what the White House wanted, according to Barbara Miller, the ABC's North America correspondent based in Washington DC: 

"The US has been trying to dissuade its ally from retaliating for the Iranian weekend strikes.

The message from the administration was that Israel should take the win.

With the help of its allies it had repelled the vast majority of the Iranian drones and missiles.

The White House announced new sanctions on Iran in a further show of solidarity with Israel.

It became increasingly clear however that Israel would act, stoking fears in Washington of an escalating tit for tat situation.

From what we know so far this appears to have been a limited action.

If that's the case, there will be hope here that Iran may draw a line.

An interview Iran's Foreign Minister gave CNN just hours before news of the apparent Israeli action is cause for concern.

Hossein Amir-Abdollahian told the network Iran would respond immediately and "at a maximum level" if Israel struck."

Here is a recap of what is being reported as information continues to come in.

Three people familiar with the matter have told Reuters news agency Israel has attacked Iran.

Iranian state media reported early on Friday that its forces had destroyed drones. 

The reports come days after Iran launched a retaliatory drone strike on Israel.

One source told Reuters the US was not involved but was notified by Israel before the attack.

Iran's Fars news agency reported three explosions were heard near an army base in the central city of Isfahan.

An Iranian official told Reuters there was no missile attack and the explosions were the result of the activation of Iran's air defense systems.

Iranian state TV said that shortly after midnight "three drones were observed in the sky over Isfahan".

"The air defense system became active and destroyed these drones in the sky," state media reported.

The broadcaster later said the situation in Isfahan was normal and no ground explosions had occurred.

The Israeli military had no comment on the reports.

We mentioned earlier that an Iranian government official and state-run TV have suggested sites may have been targeted by drones.

We now have some more information on what has been said.

Hossein Dalirian, who is a spokesman for Iran's civilian space program, said on X that several small "quadcopter" drones had been shot down.

A state television reporter in Isfahan said the same in a live report, saying "several small drones were flying in the sky over Isfahan, which were fired at".

A senior commander of Iran's army has said no damage was caused in the overnight attack, according to state TV.

He added that the noise heard overnight in Isfahan was due to air defence systems targeting a "suspicious object".

The Department of Foreign Affairs (DFAT) has "urged" Australians in Israel and the Occupied Palestinian Territories to leave "if it's safe to do so".

In updated travel advice, DFAT notes "a high threat of military reprisals and terrorist attacks against Israel and Israeli interests across the region".

"The security situation could deteriorate quickly, with little or no notice."

DFAT had already advised Australians to reconsider their need to travel to Israel and had warned against travel near Gaza or the West Bank beyond East Jerusalem.

But the request to leave is new.

DFAT warned military attacks could lead to travel disruptions including airspace closures. "Tel Aviv's Ben Gurion International Airport may pause operations due to heightened security concerns at any time, and at short notice."

A stronger 'do not travel' warning was already in place for Iran, but DFAT has updated its advice for that country, saying "regional tensions are high, and the security situation could deteriorate quickly with little or no notice."

Australian government officials have been directed not to leave the cities of Tel Aviv, Jerusalem, Ramallah and Tehran as a precaution.

'Do not travel' warnings remain in place for Iraq, Syria, Yemen and Lebanon.

Australian citizens and permanent residents can register their location and stay in contact with officials via DFAT's crisis registration portal.

Iran's Fars news agency reported three explosions were heard near an army base in the central city of Isfahan.

Malcolm Davis, an analyst at the Australian Strategic Policy Institute, has told ABC News the key facility in the area was the Natanz nuclear enrichment facility.

As we covered earlier, Iranian state media has described all nuclear sites in the area as "fully safe."

Dr Davis said it was a "harder and deeply buried target" and was one of the core aspects of Iran's potential to acquire nuclear weapons.

"There's also a series of military bases nearby that site as well as well as the Iranian Revolutionary Guard Corps bases in the region," he said.

Dr Davis said Israel could not afford to allow Iran to get nuclear weapons.

"When you look at the size of Israel, the use of a nuclear weapon against Israel by Iran would be an existential threat to Israel itself," he said.

"So, I think that Israel would have every interest in preventing Iran from getting nuclear weapons under any circumstances including if necessary through military strikes."

Here's what Allyson Horn, the ABC's Middle East correspondent in Jerusalem, says: 

"I'll start by saying you never know what's going to happen in the Middle East – and that very little is still confirmed on this unfolding issue.

But if, as it appears, these are limited, targeted drone strikes on military facilities in Iran, then it would be considered at the lesser end of the responses that Israel could have exacted.

We need to still see what the damage is in Iran, and whether there have been any civilian casualties, because that could change what Iran decides to do next.

Last weekend, Iran launched a missile barrage against Israel — most of it intercepted by the Iron Dome defence system.

And after that Iranian attack, there was a lot of internal pressure from within Israel Prime Minister Benjamin Netanyahu's cabinet, to hit-back immediately, and strike hard.

That doesn't appear to have happened – it wasn't immediate and it appears the US was given warning ahead of time. And it also appears to be only a few drones launched into Iran, targeting limited military sites.

That's not to say that the Israeli response isn't serious – it is. Israel is still directing an attack on Iranian soil, which in itself will be seen as a provocation. And Iran could decide that it has to respond.

So the threat of escalation is high – and it's real.

But, it could also be seen by Iran as an expected response by Israel – and one that didn't target civilians – therefore lessening Iran's appetite to prompt a wider-regional conflict."

ABC's North America correspondent Barbara Miller has spoken to News Channel about what we know so far as more information comes to light. 

Watch the video below to see her report.

Isfahan also is home to sites associated with Iran's nuclear program, including its underground Natanz enrichment site.

However, state television has described all sites in the area as "fully safe."

Malcolm Davis, an analyst at the Australian Strategic Policy Institute, has told ABC News Channel he would be "sceptical about Iran's claims" that it was not an attack or that the attack was defeated.

"I think all the indications are that this was an Israeli attack, but it was clearly directed against military facilities in Ishfahan rather than… the nuclear facility there," he said.

"I think that the Israelis have done a strike, it is a fairly limited strike from what I can see, just a small number of missiles.

"I think the message that the strike sends is that Iran's large strike the other weekend failed utterly due to the effectiveness of Israeli integrated air and missile capabilities, whilst Israel's strike today with a very limited number of missiles has been very successful in hitting Iranian bases there, including air force bases.

"The key question now is, how does Iran retaliate?"

Iranian state TV started a a scrolling, on-screen alert acknowledging reports of an explosion near Isfahan.

This is what it looked like.

Iran has announced it has grounded commercial flights in Tehran and across areas of its western and central regions.

Online videos appeared to show loudspeakers informing customers of the incident at Imam Khomeini International Airport in Tehran.

Some Emirates and Flydubai flights that were flying over Iran early on Friday made sudden sharp turns away from the airspace.

This screenshot of FlightRadar24 shows the flight activity over Iran.

An unnamed Iranian official has told Reuters the explosions heard in Isfahan were a result of the activation of Iran's air defence systems.

The official told Reuters that there was no missile attack carried out against Iran.

An Iranian government official and state-run TV suggested sites may have been targeted by drones, according to the Associated Press.

This is a developing story, with new information continuing to come to light.

Let's take a look at what is being reported so far:

Earlier, it was reported that warning sirens sounded in northern Israel early on Friday.

The Israeli military now says the warning sirens were a false alarm.

The sirens went off shortly after the unconfirmed reports of Israeli strikes in Iran.

Iran's FARS news agency is reporting sources as saying that: "The sound of three explosions has been heard near an army base in north-west Isfahan."

"At around 12:30am GMT [10:30am AEST], three drones were observed in the sky over Isfahan. The air defence system became active and destroyed these drones in the sky," Iranian state TV added.

Here's a map showing Isfahan's location:

Iran's Fars news agency reports explosions at an airport in the central city of Isfahan, but the cause was not immediately known.

Iran suspended flights over the cities of Isfahan, Shiraz and Tehran, state media reported.

State-run IRNA news agency reported Iran fired air defences at a major airbase in Isfahan, which long has been home to Iran's fleet of American-made F-14 Tomcats — purchased before the 1979 Islamic Revolution.

Tehran's Imam Khomeini International Airport was closed to all flights until 0700 GMT (5pm AEST), according to a notice to airmen posted on a US Federal Aviation Administration database.

Some Emirates and Flydubai flights that were flying over Iran early on Friday made sudden sharp turns away from the airspace, according to flight paths shown on tracking website Flightradar24.

- Reuters

Hello and welcome to our live coverage of the situation in the Middle East. Here's what we know:

Israeli missiles have hit a location in Iran, US defence officials have told American media organisations.

Iran's FARS news agency says explosions were heard at an  airport in the Iranian city of Isfahan, but says the cause was not immediately known.

Several Iranian nuclear sites are located in Isfahan province.

Iran's state-run IRNA news agency is reporting Iran has fired air defence batteries.

Iranian state media says the country has suspended flights over several cities.

Commercial planes have also begun diverting their routes over western Iran.

This comes after Iran attacked Israel with hundreds of drones and missiles over the weekend in retaliation for a suspected Israeli strike on its embassy compound in Syria.