At least 200 Israelis died in a surprise large-scale attack by the Palestinian militant group Hamas today, the army said, as Prime Minister Benjamin Netanyahu vowed to reduce the group's Gaza hideouts to "rubble".
Intense air strikes on the coastal enclave brought the Palestinian death toll to at least 232, Gaza officials said, following Hamas's massive rocket barrage and ground, air and sea offensive, in the conflict's bloodiest escalation in decades.
Gun battles raged into the night between Israeli forces and hundreds of Hamas fighters in at least 22 Israel locations, including at least two where gunmen were holding hostages, the army said.
"Terrorists rampaged and broke into homes, massacring civilians," the army said, adding that more than 1,000 people in Israel were wounded by gunshots or the more than 3,000 incoming rockets.
"We are at war," Mr Netanyahu told the stunned nation in the morning, after Hamas had launched its multipronged attack at dawn, half a century after the outbreak of the 1973 Arab-Israeli war.
"I'm telling the people of Gaza: get out of there now, because we're about to act everywhere with all our force," he said later.
"We'll strike them to the bitter end and avenge with force this black day they brought on Israel and its people."
He warned that "all the places in which Hamas is based, in this city of evil, all the places Hamas is hiding in, acting from - we'll turn them into rubble."
As the UN Security Council called an emergency meeting for tomorrow, President Joe Biden voiced "rock solid and unwavering" support for the US ally and warned "against any other party hostile to Israel seeking advantage in this situation".
As night fell, the Israeli army said its forces were still engaged in live gun battles in 22 Israel locations, in an ongoing operation labelled "Swords of Iron", as reservists were being called up.
"There are still 22 locations where we are engaging with terrorists that came into Israel, from the sea, from the land and from the air," said army spokesman Richard Hecht on what he labelled a "robust ground invasion".
Hamas earlier released images of several Israelis taken captive, and another army spokesman, Daniel Hagari, confirmed that "there are kidnapped soldiers and civilians.
"I can't give figures about them at the moment. It's a war crime committed by Hamas and they will pay the price."
Hecht said there was also a "severe hostage situation" in the Negev desert communities of Beeri and Ofakim east of Gaza.
The Islamist group started the multi-pronged attack around 6:30am (3.30am Irish time) with thousands of rockets aimed as far as Tel Aviv and Jerusalem, some bypassing the Iron Dome defence system and hitting buildings.
Hamas fighters - travelling in ground vehicles, motorised paragliders and boats - breached Gaza's security barrier and attacked nearby Israeli towns and military posts, opening fire on residents and passersby.
"Send help, please!" one Israeli woman sheltering with her two-year-old child pleaded as militants outside opened fire and tried to break into their safe room, Israeli media reported.
Bodies were strewn on the streets of the Israeli town of Sderot near Gaza and inside cars, the windscreens shattered by hails of bullets.
"I saw many bodies, of terrorists and civilians," one man told AFP, standing beside covered corpses on a road near Gevim Kibbutz in southern Israel.
"So many bodies, so many bodies."
Journalists for the news agency AFP witnessed Palestinian armed men gather around a burning Israeli tank, and others driving a seized Israeli military Humvee back into Gaza, where they were met by cheering crowds.
We need your consent to load this rte-player contentWe use rte-player to manage extra content that can set cookies on your device and collect data about your activity. Please review their details and accept them to load the content.Manage Preferences
Israeli army Major General Ghasan Alyan warned Hamas had "opened the gates of hell".
Smoke could be seen billowing from the remains of bombed residential towers which Gaza's interior ministry said contained 100 apartments.
Israel's military said it had warned residents to evacuate before targeting the multi-storey buildings used by Hamas.
Israel's state-run electricity company cut the power supply to Gaza as army flares lit up the night sky.
The escalation follows months of rising violence, mostly in the occupied West Bank, and tensions around Gaza's border and at contested holy sites in Jerusalem.
Before today, at least 247 Palestinians, 32 Israelis and two foreigners had been killed this year, including combatants and civilians, according to Israeli and Palestinian officials.
Hamas labelled its attack "Operation Al-Aqsa Flood" and called on "resistance fighters in the West Bank" as well as in "Arab and Islamic nations" to join the battle.
Its armed wing, the Ezzedine al-Qassam Brigades, claimed to have fired more than 5,000 rockets, while Hecht said Israel had counted more than 3,000 incoming rockets.
Hamas chief Ismail Haniyeh claimed the group was on the "verge of a great victory".
"The cycle of intifadas (uprisings) and revolutions in the battle to liberate our land and our prisoners languishing in occupation prisons must be completed," he said.
Air raid sirens wailed across southern and central Israel, as well as in Jerusalem.
In Tel Aviv, a gaping hole was ripped into a building, with residents boarding a bus to flee to safety.
The conflict sparked major disruption at Tel Aviv airport, where many carriers cancelled flights. Schools will remain closed tomorrow, the start of the week in Israel.
Hamas took control of Gaza in 2007, leading to Israel's crippling blockade of the impoverished enclave of 2.3 million people.
Israel and Hamas have since fought several wars. The last major military exchange, in May, killed 34 Palestinians and one Israeli.
In northern Gaza today, hundreds of people fled their homes, carrying food and blankets.
Violence also erupted across the West Bank, including annexed east Jerusalem, with five Palestinians killed and 120 wounded in clashes with Israeli forces and settlers, Palestinian medical services said.
'Please send help'
Speaking to Israel N12 News by phone from Nir Oz, a kibbutz near Gaza, a woman identified as Dorin said militants had infiltrated her house and tried to open the bomb shelter where she was hiding.
"They just came in again, please send help," she said.
"There are a lot of homes harmed ... My husband is holding the door closed ... They are firing rounds of bullets."
In Gaza, where Palestinians have lived under an Israeli blockade for 16 years, residents rushed to buy supplies in anticipation of days of war ahead.
Some evacuated their homes and headed for shelters.
Scores of Palestinians were killed and hundreds wounded in clashes at the border into Israel, where fighters captured the crossing point and tore down fences.
Some of those dead were civilians, among crowds that attempted to cross into Israel through the damaged gates.
"We are afraid," Palestinian woman, Amal Abu Daqqa, said as she left her house in Khan Younis.
Biden offers support to Netanyahu
Western countries, led by the United States, denounced the attack and pledged support for Israel.
"I made clear to Prime Minister Netanyahu that we stand ready to offer all appropriate means of support to the Government and people of Israel," US President Joe Biden said in a statement issued after the two men spoke on a call.
"Israel has a right to defend itself and its people. The United States warns against any other party hostile to Israel seeking advantage in this situation," Biden added.
Across the Middle East, there were demonstrations in support of Hamas, with Israeli and US flags set on fire and marchers waving Palestinian flags in Iraq, Lebanon, Syria and Yemen.
The Hamas attack was openly praised by Iran and by Hezbollah, Iran's Lebanese allies.
UN Middle East peace envoy Tor Wennesland condemned the attacks on Israel, warning in a statement: "This is a dangerous precipice, and I appeal to all to pull back from the brink."
Hamas media displayed videos of what it said were bodies of Israeli soldiers brought into Gaza by fighters, and Palestinian gunmen inside Israeli homes and driving through an Israeli town in jeeps.
Backdrop to surging violence
The escalation comes against a backdrop of surging violence between Israel and Palestinian militants in the Israeli occupied West Bank, where a Palestinian authority exercises limited self-rule, opposed by Hamas that wants Israel destroyed.
Israel itself has been experiencing internal political upheaval, with the most right-wing government in its history attempting to overhaul the judiciary.
Meanwhile, Washington has been trying to strike a deal that would normalise ties between Israel and Saudi Arabia, seen by Israelis as the biggest prize yet in their decades-long quest to be recognised by their Arab neighbours.
Timeline: Conflict between Israel and Palestinians
Palestinians fear that any such deal could sell out their future dreams of an independent state.
Saudi Arabia's foreign ministry called for an "immediate cessation of violence between Israeli and the Palestinians", the state news agency reported.
