A crackdown on nationwide protests in Iran has killed at least 538 people and even more are feared dead, activists said on Sunday (Monday AEST), while Tehran warned that the US military and Israel would be "legitimate targets" if America uses force to protect demonstrators.

More than 10,600 people have been detained over the two weeks of protests, said the US-based Human Rights Activists News Agency, which has been accurate in previous rounds of unrest in Iran in recent years.

It relies on supporters in Iran crosschecking information. It said of those killed, 490 were protesters and 48 were members of security forces.

READ MORE: Iran warns it will retaliate if Trump orders strike over protests

With the internet down in Iran and phone lines cut off, gauging the demonstrations from abroad has grown more difficult. The Associated Press has been unable to independently assess the toll.

The Iranian government has not offered overall casualty figures for the demonstrations.

Those abroad fear the information blackout is emboldening hard-liners within Iran's security services to launch a bloody crackdown. Protesters flooded the streets in the country's capital and its second-largest city again on Sunday morning.

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US President Donald Trump has offered support for the protesters, saying on social media that "Iran is looking at FREEDOM, perhaps like never before. The USA stands ready to help!!!"

Trump and his national security team have been weighing a range of potential responses against Iran including cyberattacks and direct strikes by either US or Israel, according to two people familiar with internal White House discussions who were not authorised to comment publicly and spoke on condition of anonymity.

The White House, which did not immediately respond to a request for comment, has not indicated it has made any decisions. The massive ongoing US military deployment to the Caribbean has created another factor that the Pentagon and Trump's national security planners must consider.

Defiance in parliament

The threat to strike the US military and Israel came during a parliamentary speech by Mohammad Baagher Qalibaf, the hard-liner speaker of the body who has run for the presidency in the past.

He directly threatened Israel, calling it "the occupied territory".

"In the event of an attack on Iran, both the occupied territory and all American military centres, bases and ships in the region will be our legitimate targets," Qalibaf said.

READ MORE: Body found after Longwood bushfire, blazes continue across Victoria

"We do not consider ourselves limited to reacting after the action and will act based on any objective signs of a threat."

Other politicians rushed the dais in parliament, shouting: "Death to America!"

It remains unclear how serious Iran is about launching a strike, particularly after its air defences were destroyed during the 12-day war with Israel in June. Any decision to go to war would rest with Iran's 86-year-old Supreme Leader Ayatollah Ali Khamenei.

The US military said in the Middle East it is "postured with forces that span the full range of combat capability to defend our forces, our partners and allies and US interests."

Iran targeted US forces at Al Udeid Air Base in Qatar in June, while the US Navy's Middle East-based 5th Fleet is stationed in the island kingdom of Bahrain.

Israel, meanwhile, is "watching closely" the situation between the US and Iran, said an Israeli official, who spoke on condition of anonymity due to not being authorised to speak to journalists. Israeli Prime Minister Benjamin Netanyahu spoke with US Secretary of State Marco Rubio overnight on topics including Iran, the official added.

"The people of Israel, the entire world, are in awe of the tremendous heroism of the citizens of Iran," said Netanyahu, a longtime Iran hawk.

At the Vatican, Pope Leo XIV mentioned Iran as a place "where ongoing tensions continue to claim many lives," adding that "I hope and pray that dialogue and peace may be patiently nurtured in pursuit of the common good of the whole of society".

Protests in Tehran and Mashhad

Online videos sent out of Iran, likely using Starlink satellite transmitters, purportedly showed demonstrators gathering in northern Tehran's Punak neighbourhood. There, it appeared authorities shut off streets, with protesters waving their lit mobile phones. Others banged metal while fireworks went off.

"The pattern of protests in the capital has largely taken the form of scattered, short-lived, and fluid gatherings, an approach shaped in response to the heavy presence of security forces and increased field pressure," the Human Rights Activists News Agency said.

"Reports were received of surveillance drones flying overhead and movements by security forces around protest locations, indicating ongoing monitoring and security control."

In Mashhad, Iran's second-largest city some 725 kilometres north-east of Tehran, footage purported to show protesters confronting security forces. Protests also appeared to happen in Kerman, 800 kilometres south-east of Tehran.

Iranian state television on Sunday morning had correspondents appear on the streets in several cities to show calm areas, with a date stamp shown on screen. Tehran and Mashhad were not included.

Government rhetoric ratcheted up. Ali Larijani, a top security official, accused some demonstrators of "killing people or burning some people, which is very similar to what ISIS does," referring to the Islamic State group by an acronym.

State TV aired funerals of slain security force members while reporting another six had been killed in Kermanshah. In Fars province, violence killed 13 people, and seven security forces were killed in North Khorasan province, it added. It showed a pickup truck full of bodies in body bags and later a morgue.

Even Iran's reformist President Masoud Pezeshkian, who had been trying to ease anger before the demonstrations exploded in recent days, offered a hardening tone in an interview aired on Sunday.

"People have concerns, we should sit with them and if it is our duty, we should resolve their concerns," Pezeshkian said.

"But the higher duty is not to allow a group of rioters to come and destroy the entire society."

The demonstrations began on December 28 over the collapse of the Iranian rial currency, which trades at over 1.4 million to $US1, as the country's economy is squeezed by international sanctions in part levied over its nuclear program. The protests intensified and grew into calls directly challenging Iran's theocracy.

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A couple's drive to the airport has taken a shocking turn after their hire car fell into a large sinkhole in Adelaide.

The crater at Hyde Park, caused by a burst water main, swallowed the front wheels of the Kia van, which then became stuck for two hours.

A burst main also caused an early-morning deluge on Park Street.

READ MORE: Body found in bushfire-hit area of Victoria

"We're just standing here watching the car sink and there was no one here, like I was directing traffic initially," witness Sanja Nikolic said.

The water threatened homes and flowed into a cellar below a young family's home as other residents watched it move dangerously close.

The visitors caught on their way to the airport were from the Northern Territory and making their way to return the rental car before a flight home.

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They first drove into what was a small ditch, and soon there was no turning back.

"We could still see the number plate of the car, like it was submerged maybe that much, but then over time, it's been maybe an hour," Nikolic said.

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Both the driver and her passenger managed to get out of the van and caught an Uber to the airport.

Two hours later, SA Water crews finally cut the supply, leaving about 50 homes without water.

The car was eventually pulled from the crater.

A family is grateful to be alive after they were forced to huddle together inside a shipping container as flames tore through their home.

Isabel Bafunno, 81, said they tried to put out the fire when it reached their remote Caveat property in Victoria, but "it was hopeless".

Outside, fire crews battled one of the state's fiercest blazes, named the Longwood fire.

READ MORE: Homes razed, cattle killed as fires continue to burn

Bafunno, her 59-year-old daughter, and her 92-year-old brother Peter Palmieri endured a long, anxious wait.

It wasn't until Saturday morning that the Police Air Wing chopper arrived to get them to safety.

"They're an amazing lot. They are wonderful, wonderful people, all of them in that kind of thing," she said.

Peter thought the home he built in 1976 was fireproof – but the intensity of the blaze was nothing he'd seen before.

An ember attack overwhelmed the property.

"Suddenly, I don't know maybe the heat it blew up the wall over the home, it blew up," he said.

"Everywhere you look it looked like a war, sparks everywhere."

Isabel's daughter braved the flames to save the family cat.

"We had to run into the house and it was all smoke, and we couldn't see a thing, you know," she said.

Their beloved Bubba is recovering at a nearby vet.

Air Wing Tactical Flight Officer LSC Brittany Smith said they were extremely lucky.

"By no means do we encourage people to shelter in shipping containers, however on this occasion all I can say is this family is extremely lucky," she said.

READ MORE: Deadly protests in Iran reach two-week mark as country remains without internet

"It was good we were able to get in and get them out."

Many Victorians are returning home for the first time.

In Yarck, residents are only just being let back in, stepping into the aftermath of what the fire spared, and what it didn't.

The Maroondah Highway is lined with the ruins of family homes, at least 11 have been lost in a town that has only about 30.

With fire bearing down on all sides, Bob Balsdon stood his ground armed with nothing more than a mop and a bucket.

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"Yeah, at one stage we had to because the fire truck had to go in the end," he said.

"Nobody could get water so we just fought it with buckets and mops and shovels, whatever we could to save the house."

Because it's been so hard for crews to get into Yarck, they haven't been able to assess the trees, so the Maroondah Highway has turned into a dangerous obstacle course.

A Sydney childcare centre is the first to be shut down amid a tough new crackdown, after it failed to meet national standards for more than decade.

The Fun2Learn centre at Rosehill permanently shut its doors on Friday after dozens of breaches were uncovered.

News of the shutdown was delivered to 37 families in mid-December.

READ MORE: Body found in bushfire-hit area of Victoria

Acting Early Learning Minister Courtney Houssos said: "This shouldn't come as a shock for the centre, when they have failed to meet the standards for 12 years."

While no serious child safety incident occurred, the Early Learning Commission is making no apologies for cracking down on providers.

"We'll continue to do so to rebuild the trust in parents so they know that when they drop their children at a childcare centre that they have confidence that it's in a safe and a quality environment," Houssos said.

READ MORE: Homes razed, cattle killed as fires continue to burn

Among the 41 breaches since 2023, authorities claim they found an emergency exit door at the centre padlocked shut.

Unlabelled chemicals were lying around in children's bathrooms and there was no appropriate plan for children with severe allergies.

Other breaches included consultants without proper working with children checks, children playing with dangerous objects and poor hygiene in the centre.

When 9News spoke to the owner this morning, she was distraught, adamant that she would never put a child at risk and that she was working on a continuous improvement program – one that had been set down by the department.

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Fun2Learn is the first to be closed under new tougher regulations, but between July 2024 and the end of September last year, 22 other centres were shut for breaches.

The minister said the department would work with families to find an alternative.

"We know that it can be really difficult to find a place but we have to balance that against the responsibility we have to ensure that children are safe," she said.

Owner Dev Senthiya said around 20 firefighters contained the roof blaze.

A person has died in a bushfire in Victoria and fires continue to burn out of control across parts of the state as Prime Minister Anthony Albanese and Premier Jacinta Allan visited some of the devastated areas.

Police said this afternoon that they had found human remains in an area ravaged by the Longwood bushfire.

The person has not been formally identified.

LIVE UPDATES: Towns wiped out as state remains on high alert

READ MORE: Homes razed, cattle killed as fires continue to burn

READ MORE: Deadly protests in Iran reach two-week mark as country remains without internet

"Police were able to access a fire-affected stretch off Yarck Road at Gobur this afternoon," they said.

"The remains were found around 100m from a vehicle."

Police will prepare a report for the coroner.

On Saturday, Victoria Police confirmed the safety of three formerly unaccounted for people missing after their home was destroyed in the same fire.

Three fires are burning at emergency-level in the state: the catastrophic Longwood fire in central Victoria almost two hours from Melbourne, the fire in Walwa in the state's north-east and a fire in the Carlisle River in the Otways around the Great Ocean Road.

Dozens of people have lost their homes, with about 300 structures destroyed, and cattle and wildlife have been killed and injured, including at an animal sanctuary.

READ MORE: 'Significant rain' still expected as Ex-Tropical Cyclone Koji crosses Queensland

Albanese and Allan have seen the devastation first hand and announced a multimillion-dollar relief package.

They visited the small town of Harcourt, which has been devastated.

A combined $19.5 million from the state and commonwealth has been put up to cover counselling, start the clean-up and provide emergency cash.

"This is a one-off, immediate payment of $1000 per eligible adult and $400 per child who've been severely affected," Albanese said.

"We've got your back. Not just during this crisis, but through the recovery as well."

Bianca Hitchens is still coming to grips with the loss of her home of 23 years, one of 47 destroyed in Harcourt along with three businesses.

"It's a nice gesture and it's really appreciated – but what does it get me? What does it get us?" she said.

"I don't need anything, but I need everything."

The place where she raised two children has been razed.

"I feel like everything about me was here, and it's erased. And I feel like I kind of never existed. Everything's gone," she said.

Another 150 were lost in Longwood and 30 more in Natimuk.

Across Victoria, 350 thousand hectares have been burnt.

Allan warned that will increase.

Officials say it'll take weeks to fully understand the extent of the damage with many spots still too dangerous to access even for trained crews.

But it hasn't stopped others trying to pass roadblocks to see it for themselves.

"These are not places for visitors, spectators, tourists," Emergency Management Commissioner Tim Wiebusch said.

"It is wrong to go into these firegrounds where it's unsafe and you don't belong there – and you will be dealt with by Victoria Police," Allan said.

It was the perfect end to her comeback, after being off the WTA tour since last September.

Multiple heat alerts in place today across the country, posing an ‘extreme’ fire risk.

A 51-year-old man has died at a detention centre in Sydney after being found wounded.

Emergency services were called to Villawood Immigration Detention Centre in the city's west at 6.35am today.

The man's body was found with a serious wound.

Homicide police are investigating.

READ MORE: Body found in bushfire-hit area of Victoria

Emergency services attended three accidents that disrupted traffic across the city today.