Over 1,100 people have died and thousands are injured in both Israel and Gaza after Hamas launched a surprise dawn attack on Israel on Saturday during the Jewish high holy day of Simchat Torah.
Around 700 Israelis were killed and thousands wounded by gunbattle raging in more than 20 locations inside Israel, according to Israeli television reports.
In Gaza, authorities say 413 have died and almost 2,000 wounded after Israel responded with major retaliatory air strikes.
Hamas said the attack was driven by what it said were Israel's escalated attacks on Palestinians in the West Bank, Jerusalem and against Palestinians in Israeli prisons.
Israeli Prime Minister Benjamin Netanyahu has declared his nation is at war and vowed of a "mighty vengeance".
The attacks occurred a day after the 50th anniversary of the start of the 1973 Yom Kippur War, when Israeli forces were caught off guard by Syrian and Egyptian tank columns.
Analysts ask why security agencies failed
The attacks on Israel - with its intensive infiltration and monitoring of militants - have left many surprised and shocked.
Former CIA intelligence analyst Marc Polymeropoulous described the events as “a staggering intelligence failure”.
“Hard to comprehend how this was missed,” he wrote on social media site X.
“This is Israel's 9/11.”
Former US ambassador to Israel David Friedman said he’d never seen anything like it.
“I’ve never seen the border breached in this manner," he told MSNBC.
"Usually, even one person from Gaza gets close to the border, they’re intercepted and neutralised long before they can do anything. This is just something I’ve never seen before. It’s of course a large intelligence failure.”
Former Israeli national security advisor Eyal Hulata said the attacks appeared to have been planned.
"They've been planning this for a long time," he said.
"Obviously this is a very coordinated attack, and unfortunately they were able to surprise us tactically and cause devastating damage."
Efraim Halevy, the former head of Israeli intelligence service Mossad, said the number of missiles launched from Gaza - over 3,000 - was “beyond imagination”.
He said the operation was well coordinated.
“We didn’t have an inkling of what was going on,” he told CNN.
How did the violence unfold?
Rockets
At about 6.30am (3:30pm AEDT Saturday) Palestinian Islamist group Hamas fired a huge barrage of rockets across southern Israel.
One hour later, the Israeli military said Palestinian gunmen had crossed into Israel.
Israeli soldiers stand by a pickup truck used by Palestinian militants in Sderot, Israel, on 7 October 2023. Source: AP / AP
Most fighters crossed through breaches in land security barriers separating Gaza and Israel. But at least one was filmed crossing on a powered parachute while a speedboat was filmed heading to Zikim, an Israeli coastal town and military base.
Videos from Al-Qassam Brigades, the armed wing of Hamas, show fighters taking off from Gaza and landing in what appears to be southern Israel, where shots are fired.
A screenshot taken of a video from the Al-Qassam brigades showing fighters on motorised parachutes. Credit: Supplied
Fighters on foot raided the Israeli border town of Sderot and were reported to be in another border community, Be'eri, and the town of Ofakim 30km east of Gaza, according to Israeli media citing phone calls from residents.
Bodies of Israeli civilians were strewn across the streets of Sderot, surrounded by broken glass. The bodies of a man and woman were sprawled across the front seats of a car.
The body of an Israeli man killed while driving a motorcycle in the city of Sderot, 7 October 2023. Source: EPA / EPA
The Israeli military later confirmed Israelis were being held in Gaza.
What is happening in Gaza?
Israel's military spokesperson said the air force carried out strikes in Gaza. Medics in Gaza said dozens of people were killed in the strikes.
Streets were deserted apart from ambulances racing to the scenes of air strikes. Israel cut the power, plunging the city into darkness.
In Gaza, a narrow strip where 2.3 million Palestinians have lived under an Israeli blockade for 16 years, residents rushed to buy supplies in anticipation of war. Some evacuated their homes and headed for shelters.
"We are afraid," a Palestinian woman, Amal Abu Daqqa, told Reuters as she left her house in Khan Younis.
Gaza has been devastated by four wars and countless skirmishes between Hamas and Israel since the militants took control of the strip in 2007.
What happens next?
Polymeropoulous said “a massive military response” in Gaza should be expected.
“Expect a massive military response in Gaza, including possible ground invasion, and potential for further escalation. All eyes on Iran as well.”
The Israeli prime minister's office said the security cabinet had approved steps to destroy the military and governmental capabilities of Hamas and Islamic Jihad "for many years," including cutting electricity and fuel supplies and the entry of goods into Gaza.
Smoke rises after Israeli warplanes targeted the Palestine tower in Gaza City, 7 October 2023. Source: EPA / EPA
A senior Biden administration official told reporters that the United States was working with other governments to make sure the crisis does not spread and is contained to Gaza.
- With Reuters