Israel's troops were still battling to clear out Hamas gunmen more than two days after they burst across the fence from Gaza on a deadly rampage, and the army said it would soon go on the offensive after the biggest mobilisation in Israeli history.
Fighting raged at several locations inside Israel where the fighters were still holed up after killing 700 Israelis and seizing dozens of hostages in a raid that shattered Israel's reputation of invincibility.
Israel's chief military spokesman said troops had re-established control of communities that had been overrun, but that isolated clashes continued as some Palestinian gunmen remained active.
"We are now carrying out searches in all of the communities and clearing the area," chief military spokesperson Rear-Admiral Daniel Hagari said.
The shocking images of the bodies of hundreds of Israeli civilians sprawled across the streets of towns, gunned down at an outdoor disco and abducted from their homes were like nothing seen before in the decades-old Israeli-Palestinian conflict.
Israel has already responded with its heaviest ever bombardment of the Gaza Strip, killing some 500 people so far, and could be contemplating an unprecedented ground assault of the territory it abandoned nearly two decades ago.
Hagari said 300,000 reservists had already been activated in just two days.
"We have never drafted so many reservists on such a scale," Hagari said. "We are going on the offensive."
Hamas says the attack is justified by the plight of Gaza under a 16-year blockade, an Israeli crackdown in the occupied West Bank that has been the deadliest in years, and a far-right Israeli government that talks of annexing Palestinian land. Israel and Western countries say nothing justifies the intentional mass killing of civilians.
The violence jeopardises US-backed moves towards normalising relations between Israel and Saudi Arabia - a security realignment that could have threatened Palestinian hopes of self determination and hemmed in Hamas's backer Iran.
Hamas fighters were continuing to cross into Israel from Gaza, the military said, adding that between 70 and 100 gunmen have been killed in the Beeri area since Saturday.
Fighter jets, helicopters and artillery struck over 500 Hamas and Islamic Jihad targets in the Gaza Strip overnight, with targets including Hamas and Islamic Jihad command centres and the residence of a senior Hamas official, Ruhi Mashtaa.
"The price the Gaza Strip will pay will be a very heavy one that will change reality for generations," said Defence Minister Yoav Gallant in Ofakim, one of the towns that where calm was restored after a battle with Hamas fighters who stormed through it, killing civilians and leaving with hostages.
Prime Minister Benjamin Netanyahu's options for hitting Hamas, which controls the narrow Gaza Strip that is home to 2.3 million Palestinians, could be curtailed by concern for the many Israelis seized in the raid. A full-scale invasion of Gaza, which Netanyahu has tried to avoid in his long years in power, could endanger the lives of the hostages.
In a statement, the Israeli Air Force said it dropped some 2000 munitions and more than 1000 tonne bombs on Gaza aimed at over 8000 targets in Gaza in the last 20 hours. Among the targets were three rocket launchers directed at Israel, a mosque where militants were operating and 21 high-rise buildings that served militant activity.
US President Joe Biden spoke to Netanyahu for the second straight day, saying in a post on the social media platform X that he expressed "my full support for the people of Israel in the face of an unprecedented and appalling assault by Hamas terrorists."
Since Saturday, at least 493 people were killed and more than 2750 people were wounded, said the Health Ministry in Gaza.
"The Zionist enemy's military targeting and bombing of homes inhabited by women and children, mosques and schools in Gaza amount to war crimes and terrorism," Hamas official Izzat Reshiq said in a statement.
Retired Israeli military spokesperson Lieutenant Colonel Jonathan Conricus said Israel had called up around 100,000 soldiers.
"Our job is to make sure that at the end of this war, Hamas will no longer have any military capabilities to threaten Israeli civilians with, and in addition to that we also need to make sure Hamas will not govern the Gaza Strip," he said.
