Israel has declared it's a nation at war as the death toll of the conflict has risen to at least 600 people, according to local media reports.
All the latest developments as fighting continues between Israel and Hamas.
Israel's Security Cabinet declared the country is at war
Israeli Prime Minister Benjamin Netanyahu’s office says his Security Cabinet has declared the country at war following a deadly Hamas assault in southern Israel.
The decision, announced on Sunday, formally authorizes “the taking of significant military steps,” it said in a statement.
“The war that was forced on the State of Israel in a murderous terrorist assault from the Gaza Strip began at 06:00 yesterday,” it said.
It gave no further details. But Netanyahu had previously declared the country at war, and the military has promised a harsh response in Gaza.
Palestinians seek refuge in UN schools
The UN agency for Palestinian Refugees, UNRWA, said over 20,000 people were sheltering in 44 of its schools around Gaza by Saturday evening.
“The number (of displaced) is rapidly increasing, “ said Inas Hamdan, acting public information officer in Gaza.
The agency said three of its schools suffered “collateral” damage from Israeli airstrikes. The agency also said its operations of nine water wells around the Gaza Strip were stopped early on Saturday. Operations in three wells resumed on Sunday, said Hamdan.
The agency’s food distribution centres, which provide for over 540,000 Gaza residents, have been closed since Saturday.
Hundreds killed since Saturday
The death toll in Israel following a surprise attack by the militant group Hamas stands at 600, according to several Israeli media outlets.
The Kan public broadcaster and Channel 12, as well as the Haaretz and Times of Israel newspapers, reported the toll on Sunday.
There has been no official confirmation of the number of deaths on the Israeli side since the fighting erupted early on Saturday.
Palestinian officials say more than 300 people have been killed in Gaza, without differentiating between fighters and civilians.
Netanyahu says there will be a 'long and difficult' war
Israeli forces on Sunday tracked down hundreds of Palestinian fighters who infiltrated into their territory and bombarded the Gaza Strip after Prime Minister Benjamin Netanyahu spoke of a "long and difficult" war against Hamas.
The surprise offensive, launched at dawn on Saturday by the Palestinian Islamist movement Hamas in power in Gaza, left hundreds dead on both sides.
"The first phase is being completed... with the elimination of the vast majority of enemy forces that have infiltrated our territory," Netanyahu said, warning the Israelis that they were "embarking on a long and difficult war.”
The army announced that it would evacuate all residents living near the Palestinian territory in the next 24 hours.
On Sunday, Israeli forces regained control of the Sderot police station, bordering Gaza, after "neutralising 10 terrorists who were there", according to police.
The Israeli authorities have not provided any figures on the civilians and soldiers kidnapped by Palestinian fighters, but the Israeli online news site Ynet puts forward "an estimate of around a hundred people".
Hamas and Islamic Jihad, another armed Palestinian group, claimed to have captured "numerous soldiers" from Israel.
Schools will remain closed on Sunday, the start of the week in Israel.
UN Peacekeepers call for restraint
Lebanon’s Hezbollah militant group fired dozens of rockets and shells on Sunday at three Israeli positions in a disputed area along the country’s border with Syria’s Israeli-occupied Golan Heights.
Hezbollah said in a statement that the attack using “large numbers of rockets and shells” was in solidarity with the “Palestinian resistance.” It said the Israeli positions were directly hit.
A UN peacekeeping force deployed along Lebanon’s southern border called for “everyone to exercise restraint” and make use of the force's “liaison and coordination mechanisms to de-escalate” and prevent a fast deterioration of the security situation.
It said it had detected several rockets fired from southeast Lebanon toward “Israeli-occupied territory,” followed by artillery fire from Israel toward Lebanon.
Israel’s military fired back at the Lebanese areas, but there was no immediate word on casualties.
Rockets fired overnight
Before daybreak on Sunday, rockets were fired from Gaza towards Israel, hitting a hospital in the coastal town of Ashkelon. The hospital sustained damage, said senior hospital official Tal Bergman.
There was no report of casualties.
Israeli airstrikes in Gaza had intensified after nightfall, flattening residential buildings in giant explosions, including a 14-story tower that held dozens of apartments as well as Hamas offices in central Gaza City.
Around 3 am, a loudspeaker atop a mosque in Gaza City blared a stark warning to residents of nearby apartment buildings: Evacuate immediately. Just minutes later, an Israeli airstrike reduced one nearby five-story building to ashes.
After one Israeli strike, a Hamas rocket barrage hit four cities, including Tel Aviv and a nearby suburb. Throughout the day, Hamas fired more than 3,500 rockets, the Israeli military said.
Netanyahu says Israel will cut off supplies to Gaza
Israel will stop supplying electricity, fuel and goods to Gaza, according to a statement from Prime Minister Benjamin Netanyahu's office Saturday night. Much of Gaza was already thrown into darkness by nightfall after electrical supplies from Israel, which supplies almost all of the territories' power, were cut off earlier in the day.
Israel's allies express their unconditional support
On Saturday, Western allies expressed their unconditional support for Israel. The United States warned "any party hostile to Israel" from exploiting the situation.
US President Joe Biden added that his country's support for Israel was "rock solid and unwavering"
"In this moment of tragedy, I want to say to them and to the world and the terrorists everywhere: the United States stands with Israel," he said. ” We will not ever fail to have their back."
European Commission President Ursula von der Leyen condemned what she called a "senseless attack carried out by Hamas against Israel" amid a day of unprecedented violence in the region.
Speaking to attendees of the two-day gathering of the Renaissance political party in Bordeaux, von der Leyen branded the attack as "terrorism" and said that Israel had the right to defend itself.
She also said the European Union "stands with Israel", and that the "ordeal" would be the latest in a long list of challenges that would be "overcome together".
Support for Hamas
Thousands in Turkey's capital Istanbul participated in a march called "March for Fatah" to support the Palestinians.
It was a response echoed in Sanaa in Yemen, where thousands of pro-Palestine Yemeni supporters took to the streets with Palestinian flags on Saturday to celebrate Hamas' surprise attack on Israel.
In Beirut, Lebanon, hundreds of Hezbollah supporters took to the streets, waving the Palestinian flags together with the Hezbollah flag and chanting supportive slogans while others distributed celebratory sweets to passers-by.
Supporters hailed Hamas' operation and considered it a victory for the resistance against Israel. Others expressed their joy and happiness and announced the 7th of October as a day of victory.
While in Iran, lawmakers chanted "death to Israel" in their parliament chamber on Saturday after Hamas' unprecedented, wide-ranging incursion into Israel.
Airlines suspend flights to Israel
Airlines cancelled more than 80 flights to and from Tel Aviv by Saturday evening — roughly 14% of all flights scheduled — because of the unprecedented attack in Israel by the militant group Hamas, according to FlightAware.
Delta Air Lines and American Airlines cancelled flights Saturday night and Sunday night from New York’s JFK Airport to Tel Aviv, although a Delta return flight was able to depart Tel Aviv Saturday night. United Airlines also cancelled a Saturday flight from San Francisco. An earlier United flight turned around over Greenland and returned to San Francisco.
German carrier Lufthansa cancelled several flights between Frankfurt and Tel Aviv.
British man among the dead
A young British Jewish man fighting with the Israeli army was killed in the Hamas attack, his family said on Sunday, while another remains "missing" after he was lost near the Gaza border.
London resident Gaby Shalev confirmed the death of her brother Nathanel Young on Facebook.