Thousands of people - Israelis, Palestinians and foreigners - have been killed since Hamas militants attacked Israel from Gaza six days ago.
Most were civilians, with horror stories emerging about the militants' rampage and the devastating military retaliation it provoked.
Israel has vowed to crush Hamas and looks poised to send ground troops into the densely populated besieged enclave, as calls mount for a humanitarian corridor to be opened and offers to broker peace come in.
This is what we know about the war so far:
How did it start?
Hundreds of Hamas gunmen attacked Israel from Gaza at dawn on Saturday, on the Jewish holiday of Simchat Torah.
The Iran-backed Islamists said they fired around 5,000 rockets into Israel, 50 years and one day after the start of the 1973 Arab-Israeli war.
The offensive, dubbed "Operation Al-Aqsa Flood", saw them breach security fences surrounding the heavily fortified enclave using explosives and bulldozers.
They then streamed into Israel on motorbikes, pickup trucks, motorised gliders and speed boats, targeting nearby communities in the south.
At a music festival near Kibbutz Reim, close to Gaza, hundreds of young Israelis and foreigners were gunned down at close range.
Those who managed to escape were shot at in the desert scrub or as they tried to flee in their cars along the road.
Some hid under bloodied bodies until the military arrived hours later.
Israel said about 270 were killed in total.
More than 100 civilians, including children, were killed at the Kfar Aza kibbutz, according to Israeli forces.
Many died when their homes were set on fire, they added. But Hamas disputed the account, calling it a "fake and false Israeli narrative".
How has Israel reacted?
Israel declared war on Hamas on Sunday and has since fired thousands of munitions at Gaza targets from land, air and sea, flattening entire neighbourhoods and sending frightened residents fleeing for safety.
UN humanitarian agency OCHA, citing Palestinian authorities, said more than 2,500 homes have been destroyed or made uninhabitable by the bombing.
The UN agency for Palestinian refugees (UNRWA) is sheltering more than 60 percent of the 423,000 people displaced in recent days in Gaza, which is home to about 2.4 million people and has been blockaded since 2006.
Israel's Defence Minister Yoav Gallant on Monday ordered a "complete siege" of Gaza, meaning "no electricity, no food, no water, no gas".
The UN criticised that as a possible violation of international law.
Israel's military has called up around 300,000 reservists and massed tens of thousands of troops and heavy armour near Gaza, for a campaign it has dubbed "Swords of Iron".
Top officials said on Tuesday that troops had largely reclaimed the embattled south and the border around Gaza.
Holdout Hamas fighters have been dislodged from more than a dozen communities, it added.
Israel's Prime Minister Benjamin Netanyahu has formed an emergency unity government for the duration of the war.
Watch: Background to Israel-Gaza conflict explained
What is the death toll?
Israel says Hamas gunmen have killed more than 1,200 people and wounded over 2,700 in Israeli cities, towns and kibbutz communities.
The military said 258 Israeli soldiers have been killed and the bodies of 1,500 Islamist militants have been found in recaptured areas.
Among the foreigners killed were at least 25 US citizens, Secretary of State Antony Blinken said.
Israeli strikes on the coastal enclave have killed more than 1,530 people since Saturday, including 500 children, according to the health ministry in Gaza.
What about the hostages?
Israel estimates Hamas has taken more than 150 people hostage - Israelis, foreigners, and dual nationals.
The army confirmed it has contacted the families of 120 captives. Hamas has threatened to kill them one by one if civilian targets are bombed without advance warning.
The International Committee of the Red Cross said it was in contact with Hamas and Israel to try to facilitate the release of the hostages.
Turkish President Recep Tayyip Erdogan has launched a negotiation process with Hamas to release abductees and says he is willing to act as an intermediary.
Hamas has ruled out negotiating a prisoner swap with Israel while the military operation continues.
Read more: Israeli newlyweds in Ireland say relatives kidnapped by Hamas
Is the conflict limited to Gaza?
No. There have been days of back-and-forth shelling with the Iran-backed Shiite militant group Hezbollah on Israel's northern border with Lebanon.
Israel on Tuesday exchanged fire with militants in Syria, where Iran backs the government, after the army said munitions were fired towards the occupied Golan Heights.
Yesterday, Israeli strikes knocked out of service Syria's two main airports at Damascus and Aleppo.
Israel's ambassador to Germany, Ron Prosor, said the strike on Damascus airport was intended to stop "weapons deliveries from Iran".
Read more: Who is Mohammed Deif? The man behind the Hamas attack
What has Hamas said?
Hamas chief Ismail Haniyeh vowed to press ahead with "the battle to liberate our land and our prisoners languishing in occupation prisons".
There were about 5,000 Palestinians held in Israeli prisons, including 160 children and more than 1,000 who were detained without charge, according to a July UN report.
Hamas has called on "resistance fighters in the West Bank" as well as in "Arab and Islamic nations" to join the battle.
How has the world reacted?
The United States has led Western support for Israel, with President Joe Biden vowing "rock solid and unwavering" backing for Israel.
Mr Blinken delivered the message in person yesterday.
Washington has sent additional military support to Israel, including missiles for its "Iron Dome" interceptor system, and is deploying hostage experts.
Biden urged Israel to exercise restraint and follow the rules of war in its response, while NATO said it had to do so with "proportionality".
The UK is sending maritime patrol and surveillance aircraft to the eastern Mediterranean "to track threats to regional stability such as the transfer of weapons to terrorist groups", London said.
Iran has celebrated the Hamas assault, but has repeatedly denied allegations it had a role in it.
What's happening in Gaza?
Fuel, food and water are running low in Gaza because of the Israeli strikes and siege, prompting calls for immediate humanitarian aid to be sent.
The first shipment arrived in Egypt's Sinai on Thursday from Jordan but it was not immediately clear when it would get into Gaza.
