Israeli forces battled holdout Hamas fighters and pounded targets in the Gaza Strip Sunday as Prime Minister Benjamin Netanyahu warned of a "long and difficult" war ahead sparked by the Palestinian militant group's massive surprise attack.

The Israeli army said tens of thousands of soldiers were deployed to fight militants in southern desert regions near the coastal enclave, to rescue Israeli hostages and then evacuate the entire region within 24 hours.

"We'll reach each and every community till we kill every terrorist in Israel," vowed military spokesman Daniel Hagari, a day after hundreds of Hamas fighters crossed into Israel using vehicles, boats and even motorized paragliders.

"Our mission for the upcoming 24 hours is to evacuate all residents" from communities around the Gaza Strip, he told journalists amid the fighting that has left hundreds dead on both sides.

Israel also came under attack from the north on Sunday when Lebanon's Hezbollah movement launched missiles and artillery shells "in solidarity" with the unprecedented Hamas offensive.

Israel was shocked when Gaza's rulers Hamas launched a multi-pronged assault at dawn Saturday with thousands of rockets and ground, air and sea forces, attacking and infiltrating Israeli towns and kibbutz communities.

The worst fighting in decades has killed more than 200 Israelis and wounded over 1,000, leaving bodies of civilians strewn on roads, while on the Gaza side at least 313 have died and over 1,700 were reported wounded.

An unknown number of Israeli soldiers and civilians were abducted into Gaza as hostages, sparking dismay in Israel and massively complicating its military retaliation campaign.

According to the Israeli news website Ynet, "dozens of Israeli captives, including numerous women, children and elders, are believed to have been taken into the Gaza Strip".

Gun battles raged Sunday between Israeli forces and hundreds of Hamas fighters in multiple locations, including at a police station in Sderot where police and special forces "neutralized 10 armed terrorists", police said.

"A lot of people have been killed," said another army spokesman, Richard Hecht, after the military released the names of 26 fallen soldiers. "We lost soldiers, lost commanders and lost a lot of civilians.

"We are completing efforts to retake full control of Israeli territory from Hamas," he added, reporting that the army had struck 426 Hamas targets including Gaza tunnels, buildings and other infrastructure.

– 'No respite' –

Global concern has mounted, with Western capitals condemning the attack by Hamas, which Washington and Brussels consider a terrorist group, while Israel's foes, including Iran and Hezbollah, praised the assault.

Netanyahu — who leads a hard-right government but has received support from political opponents during Israel's national emergency — has vowed to turn Hamas hideouts "to rubble" and urged Palestinians there to flee as devastating air strikes continued.

"We are embarking on a long and difficult war that was forced on us by a murderous Hamas attack," Netanyahu wrote on X, formerly Twitter.

"The first stage is ending at this time with the destruction of the vast majority of the enemy forces that infiltrated our territory," he added, pledging no "respite" until victory.

US President Joe Biden on Saturday voiced "rock solid and unwavering" support for its key regional ally Israel and warned "against any other party hostile to Israel seeking advantage in this situation".

But early Sunday Lebanon's Iran-backed Hezbollah movement joined the fray from the north.

It said it had fired "large numbers of artillery shells and guided missiles" at positions in contested border areas "in solidarity" with Hamas.

"The Islamic resistance (Hezbollah)… attacked three positions of the Zionist enemy in the occupied Lebanese Shebaa farms… with large numbers of artillery shells and guided missiles," it said in a statement.

Israel's army massed tanks in the northern region after earlier firing artillery on Lebanon in response to a shot from the area.

– 'Liberate our land' –

Hamas has labeled its major 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 attack came half a century after the outbreak of the 1973 Arab-Israeli war, stunning Israel during a Jewish holiday and sparking bitter recriminations inside the country on what was widely seen as an enormous intelligence failure.

Hamas chief Ismail Haniyeh on Saturday predicted "victory" and vowed to press ahead with "the battle to liberate our land and our prisoners languishing in occupation prisons".

Hamas said Saturday it had fired 5,000 rockets, while Israel reported some 3,000 incoming projectiles. Several bypassed the Iron Dome missile defense system and smashed into buildings as far as Tel Aviv.

Under the cover of the rocket barrage, Hamas fighters smashed the militarised Gaza border fence and crossed into Israel.

Israel responded by rushing forces to the embattled south, calling up reservists and hitting Gaza in operation "Swords of Iron", with some observers predicting a possible ground invasion of Gaza.

Israeli attacks have reduced several Gaza residential towers to rubble in what Israel said were strikes aimed at Hamas facilities and which had followed warning calls for people inside to evacuate.

Hamas took control of Gaza in 2007, leading to Israel's crippling blockade of the impoverished enclave of 2.3 million people on the Mediterranean coast.

Israel and Hamas have fought several wars since, with the latest large-scale military exchange in May killing 34 Palestinians and one Israeli.

The Hamas offensive 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 Saturday, the conflict so far this year had killed at least 247 Palestinians, 32 Israelis and two foreigners, including combatants and civilians, according to Israeli and Palestinian officials.

Violence has flared again in the West Bank since Saturday, leaving at least seven Palestinians dead in clashes, according to the health ministry in Ramallah.  (by Jay DESHMUKH and AFP bureaus in Israel and Palestinian territories)

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