Iranian state media reports explosions at airport in central Iran

Iranian state media has reported that explosions have been heard at Isfahan airport in central Iran, amid conflicting reports from United States and Iranian officials about what caused them.

Australia said it was "extremely concerned" about the potential for "further escalation" in the region, with the Department of Foreign Affairs and Trade (DFAT) urging Australian citizens to leave Israel and Occupied Palestinian Territories.

Sources told the FARS news agency that Iran's air defence system was activated in Isfahan province against "an object suspected to be a drone".

"The sound of three explosions has been heard near an army base in north-west Isfahan," the sources reportedly said.

"At around 12:30am GMT (10:30am AEDT), 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.

Look back at how Friday's events unfolded in our blog.

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

It comes as an unnamed US official told US broadcaster ABC that missiles were fired by Israel.

This assertion was disputed by an Iranian official who told Reuters that the explosions heard in Isfahan were a result of Iran firing its air defence batteries.

The Iranian official added that no missile attack was carried out against Iran.

The US official could not confirm whether Syria and Iraq were hit as well, after initial reports that explosions were also heard at those sites.

According to a military source cited by Syrian state media, an Israeli missile attack targeted air defence positions in Syria's southern region.

The Israeli military said that warning sirens which sounded early on Friday in northern Israel were a false alarm. 

Senior Hamas official Sami Abu Zuhri told Reuters on Friday that Israel's "aggression" on Iran was an escalation against the region.

Australia's acting foreign minister, Katy Gallagher, said Australia remained "extremely concerned" about the potential for "further escalation of conflict" in the Middle East.

"This is in no one's interests. We urge all parties to exercise restraint and step back to avoid a further spiral of violence," she said.

"Australia will continue working with partners to try to reduce tensions and prevent further regional spillover."

The Australian government has updated its travel advice for Iran, which already had a "do not travel" warning in place, saying "regional tensions are high, and the security situation could deteriorate quickly with little or no notice". 

The Department of Foreign Affairs and Trade (DFAT) also updated its advice for Israel and the Occupied Palestinian Territories to leave "if it's safe to do so".

It said there was a "high threat of military reprisals and terrorist attacks against Israel and Israeli interests across the region". 

While 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, the request to leave is new.

It added that Tel Aviv's Ben Gurion International Airport could "pause operations due to heightened security concerns at any time, and at short notice".

Flights were seen diverting away from Iran's Isfahan province.(Supplied: Flightradar24)

Earlier, flight tracking websites showed multiple flights being diverted away from Iranian airspace.

Iran closed its airports in Tehran, Shiraz and Isfahan after the incident and cleared flights from the western portion of its airspace for a few hours after the attack, according to flight tracking website FlightRadar24.

By 4:45am GMT (3:45pm AEDT), the airports and airspace had reopened, and closure notices posted on a US Federal Aviation Administration database had been removed.

Before the airports reopened, Flydubai said it had cancelled its Friday flights to Iran. One of its earlier flights turned back to Dubai, it had said.

The reports come just days after Iran launched hundreds of drones and missiles towards Israel, pictured.(Reuters: Ronen Zvulun)

According to Reuters, several Iranian nuclear sites are located in Isfahan province, including Natanz, which is considered the centrepiece of Iran's uranium enrichment program.

The International Atomic Energy Agency said it was monitoring the situation closely and that there was no damage to the nuclear sites.

Over the weekend, Iran launched hundreds of drones and missiles in a retaliatory strike after a suspected Israeli strike on its embassy compound in Syria.

Western states sought out to send Iran messages via Türkiye in recent days to reiterate appeals for de-escalation, a Western diplomat said on Friday, Reuters reported.

The messages were conveyed before reported Israeli attacks on Iran early on Friday, after which Tehran indicated it had no plans for further retaliation.

After Iran's retaliatory attack on Israel over the weekend, Türkiye's foreign ministry confirmed it had contact with Iran and the United States in a statement, saying Ankara had called for restraint and warned of a regional war if tensions escalated further.

"In recent days we have sought to send Iran messages via Türkiye — particularly reiterating the message of de-escalation," said a Western diplomat, when asked about messages carried to Tehran by Ankara.

Türkiye's foreign ministry has not responded to Reuters for comments.

Acting US Under Secretary of State John Bass, travelled to Ankara earlier this week and met Türkiye's top diplomat Hakan Fidan.

"They discussed the critical importance of preventing further escalation or a wider conflict in the region," a US official said.

Most of the drones and missiles were downed before reaching Israeli territory.

Israel had said it was going to retaliate against Iran's April 13 missile and drone attack.

ABC/wires