Iranians face a nationwide internet blackout as Israeli strikes continue to pummel the country, including the capital Tehran.
NetBlocks, an internet watchdog run by British human rights advocate Alp Toker, reported mid-Thursday (Australia time) that Iran had been offline for more than 12 hours.
It said authorities had imposed a nation-wide internet shutdown, citing Israel's alleged "misuse" of the network for military purposes.
"The measure continues to hinder residents' access to information at a critical time," NetBlocks said.
Since Israel first attacked Iran last Friday, Iranian authorities have regularly placed partial restrictions on internet access for the country's roughly 90 million people — even as many sought to flee their homes to safer locations.
Iranian authorities have reported at least 224 deaths, mainly civilians, as the result of Israel's bombing campaign — but have not updated that toll for days.
A number of senior military leaders and scientists involved in Iran's nuclear program have been killed in strikes on their homes in apartment blocks, which authorities said also killed scores of civilians.
The Washington-based group Human Rights Activists said on Thursday that at least 639 people — of whom it had identified 263 civilians and 154 security force personnel — had been killed in Iran.
Israel has said 24 people, all civilians, have been killed in Iran's retaliatory strikes.
Ali Vaez, Iran project director with the Washington-based think tank Crisis Group, said it was unclear why Iranian authorities had blocked the internet.
"One possible reason could be that they're worried about an Israeli cyber attack that could either tap into sensitive information or paralyse some of the critical infrastructure in the country," he said.
"There might also be damage to some of the infrastructure that provides internet," Dr Vaez said.
"The regime might also be potentially interested in trying to prevent communication out of fear it would allow mobilisation from inside the country as some sort of popular or foreign-led uprising against the regime."
Israeli Prime Minister Benjamin Netanyahu has spoken about the need for regime change in Tehran.
Speaking after the first strikes against Iran last week he said, addressing Iranians, that: "As we achieve our objective, we are also clearing the path for you to achieve your freedom.
"The regime does not know what hit them, or what will hit them. It has never been weaker. This is your opportunity to stand up and let your voices be heard," Mr Netanyahu said.
Iran's Supreme Leader Ayatollah Ali Khamenei said that Iran would not surrender in comments carried by semi-official news agency Tasnim.
"War will be met with war, bombing with bombing, and strike with strike," he said.
"Iran will not submit to any demands or dictates."
'Terrified' Iranians told to delete WhatsApp
In response to internet restrictions, tech billionaire Elon Musk said on his social media platform X over the weekend that he had activated the Starlink satellite communications system in Iran.
The internet there was already heavily censored and authorities have previously shut off or restricted internet access to suppress popular dissent, including in 2022 after the death of Mahsa Amini which sparked anti-regime women's rights protests.
Iranian officials blocked access to WhatsApp in the wake of those protests until late 2024.
On Tuesday (Tehran time), Iranian state television told Iranians to remove the WhatsApp messaging platform from their phones, claiming that the app was sending user information to Israel.
WhatsApp, which is owned by Meta, said this was "false information that we're concerned will be used as an excuse to block WhatsApp at a time when people need it the most".
"All of your personal messages and calls are end-to-end encrypted so we cannot see them," WhatsApp said in a statement.
"We do not track your precise location. We do not keep logs of the personal messages people are sending one another.
"We do not provide bulk information to any government," it said.
The ABC's attempts to contact a source in Tehran via WhatsApp on Thursday were unsuccessful.
Iranians have also reported having difficulty accessing cash or making online payments due to disruptions to the country's banking systems.
CNN's chief international anchor Christiane Amanpour, who is British-Iranian, told ABC Radio National she was in contact with family and some friends in Iran.
"They are, at least my family, trying to do their best to evacuate to various homes inside Tehran but they can't get out because the roads are gridlocked, they don't have gasoline," she said.
"The financial system has been hacked so therefore it's hard to pay for what you need. If this goes on, they might run out of provisions."
Predatory Sparrow, an Israel-linked hacking group known by its Persian name Gonjeshke Darande, earlier in the week claimed a major cyber attack against the Iranian financial institution Bank Sepah.
The hacking group said Bank Sepah was "an institution that circumvented international sanctions and used the people of Iran's money to finance the regime's terrorist proxies, its ballistic missile program and its military nuclear program".
Crisis Group's Dr Vaez said the Iranian population was terrified — particularly because state media had extensively covered the war in Gaza since October 7, 2023.
"They have seen the degree of bloodshed and civilian casualties in Gaza, and they know that, you know, Israel doesn't necessarily distinguish between civilians and its prime targets and so they're terrified," he said.
Palestinian authorities say more than 55,000 people have been killed during Israel's war against Hamas.
The war in Gaza erupted after Hamas-led militants raided Israel and took 251 hostages and killed 1,200 people, most of them civilians, on October 7, 2023, Israel's single deadliest day.
Israel has maintained that its military operations are conducted in self-defence and that it takes steps to mitigate civilian harm.
Dr Vaez said that unlike in Israel, there were no bomb shelters for civilians in Iran so people felt especially unprotected and vulnerable.
"This is a regime that was not offering anything on social freedoms or economic prosperity or political participation. It was only offering security," he said.
"Now even on that front, it is failing and there's a sense of despair inside the country."
