ISRAEL HAS MASSED tens of thousands of troops around the Gaza Strip today, as gunfights rage between Hamas and Israeli forces, two days after the Islamist militants attacked Israel.

More than 1,100 people have been killed on both sides since the Iran-backed Hamas launched the massive assault at dawn on Saturday, which the Israeli army dubbed “by far the worst day” in the country’s history.

This is what we know about the conflict so far:

How it unfolded

The Israeli Army said hundreds of Hamas militants attacked Israel from around 6.30am local time on Saturday (around 4.30am Irish time), the Jewish holiday of Simchat Torah.

Muhammad Deif, the leader of the military wing of Hamas, said the group had decided to launch an “operation” so that “the enemy will understand that the time of their rampaging without accountability has ended”.

The assault also came 50 years and one day after the outbreak of the 1973 Arab-Israeli war.

Hamas fired thousands of rockets into Israel from Gaza as its militants used explosives and bulldozers to break through the fence surrounding the blockaded Palestinian enclave.

Using motorbikes, pickup trucks, motorised gliders and speed boats, the militants streamed into Israeli urban areas including Ashkelon, Sderot and Ofakim, which is about 22 kilometres from Gaza.

Shortly after 7.30am local time (5.30am Irish time), the Israel Defence Forces confirmed that Hamas fighters had crossed from Gaza into southern Israel.

The scale of the attack became clear with air raid sirens going off in major cities such as Jerusalem and Tel Aviv.

Shortly after 10.30am local time (8.30am Irish time), Israel started to strike targets in Gaza.

How Israel is responding

In a press statement on Saturday, Israeli Prime Minister Benjamin Netanyahu said Israel was “at war” with Hamas.

“We are at war, not in an operation or in rounds, but at war,” the Israeli leader said in a statement, adding Hamas had launched a “murderous surprise attack” on Israel and its people.

“I have ordered an extensive mobilisation of reserves and that we return fire of a magnitude that the enemy has not known. The enemy will pay an unprecedented price,” he said.

Netanyahu later warned Palestinians living near Hamas sites in Gaza to leave as he vowed to turn its hideouts into “rubble” in an operation it has dubbed Swords of Iron.

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.

“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 in a brief televised statement.

Israel said Hamas has taken more than 100 hostages in Israel to date. They include an unknown number of Americans and Germans.

The gunmen also carried out a bloody attack on a music festival attended by hundreds of young Israelis and foreigners near Kibbutz Reim, close to Gaza.

Irish-Israeli woman Kim Damti (22) is among those who remains unaccounted for following the attack on the festival. 

Today the Israeli army declared its forces were now “in control” of the southern communities attacked by Hamas gunmen. The army said it struck 500 Hamas and Islamic Jihad sites overnight, after carrying out 800 previously.

It has massed tens of thousands of troops and heavy armour near Gaza, with Palestinians bracing for a potential ground assault.

Defence Minister Yoav Gallant today ordered a “complete siege” on Gaza.

“We are putting a complete siege on Gaza… No electricity, no food, no water, no gas — it’s all closed,” Gallant said in a video statement, referring to the crowded enclave home to around two million people.

“We are fighting animals and are acting accordingly,” Gallant said in Hebrew.

The United Nations said more than 123,000 people have been displaced inside Gaza since the outbreak of violence.

Israel has maintained a land, air and sea blockade on Gaza since 2007 that has had a devastating effect on Palestinian civilians.

What Hamas says about the offensive

Hamas said it fired 5,000 rockets in an offensive it has branded Operation Al-Aqsa Flood.

Its chief Ismail Haniyeh on Saturday vowed to press ahead with “the battle to liberate our land and our prisoners languishing in occupation prisons”.

Hamas has called on “resistance fighters in the West Bank” as well as in “Arab and Islamic nations” to join the battle.

Early on Sunday, Lebanon’s Iran-backed Shiite militant group Hezbollah said it launched missiles and artillery shells into northern Israel “in solidarity” with the Hamas offensive.

The Israeli army said it retaliated with artillery fire.

Elsewhere, media outlets in Egypt said a policeman opened fire on an Israeli tour group in the northern city of Alexandria on Sunday, killing two Israelis and one Egyptian.

More than 1,100 killed

Israel says Hamas gunmen have killed more than 700 people and wounded over 2,000 in Israeli cities, towns and kibbutz communities.

AFP journalists have seen the bullet-riddled bodies of civilians lying on the streets in at least three locations in Israel: the city of Sderot, the nearby kibbutz of Gevim and Zikim beach north of the Palestinian coastal enclave.

An estimated 250 people were killed at the Supernova music festival near Kibbutz Reim, a volunteer who helped recover the bodies for the said.

“They butchered people in cold blood in an inconceivable way,” Moti Bukjin, a spokesman for the humanitarian organisation Zaka, said. 

On the Gaza side, health officials said at least 430 people had been killed and more than 2,200 wounded, taking the combined toll to more than 1,100 dead.

The United States said at least four Americans were killed, with the toll likely to rise. A Briton, 12 Thais and 10 Nepalis are among other foreigners killed.

How Ireland and the world has reacted

Tánaiste and Foreign Affairs Minister Micheál Martin on Saturday said he “fears for” people in Gaza as Israel retaliates after an attack by militant group Hamas.

“This was in my view an appalling attack by Hamas, and one which they know the consequences [of] as well,” he told reporters ahead of the Fianna Fáil President’s Dinner in Dublin.

“I fear for people in Gaza in terms because we’ve seen what has happened before and there needs to be a political will towards a political solution.”

Martin earlier condemned the attacks on X, formerly Twitter, calling for an immediate end to the violence.

“I strongly condemn the firing of rockets into Israel by Hamas and attacks against Israel from Gaza. I deeply regret the loss of life and the impact on civilians. I call for an immediate cessation of all hostilities,” Martin posted.

United Nations Secretary-General Antonio Guterres condemned “in the strongest terms” Hamas’ attack on Israel and called for “diplomatic efforts to avoid a wider conflagration”.

US President Joe Biden said the United States’ support for its key ally Israel was “rock solid and unwavering”. The White House said on Sunday he had ordered “additional support” for Israel and moved an aircraft carrier group to the eastern Mediterranean.

- © AFP 2023 with additional reporting by Órla Ryan