JERUSALEM >> Israeli Prime Minister Benjamin Netanyahu told the nation Saturday night that the military has opened a “second stage” in the war against Hamas by sending ground forces into Gaza and expanding attacks from the ground, air and sea.

Casting the war as a fight for his country’s very survival, he warned that the assault would intensify ahead of a broad ground invasion into the territory.

“There are moments in which a nation faces two possibilities: to do or die,” Netanyahu said. “We now face that test and I have no doubt how it will end: We will be the victors. We will do and we will be the victors.”

The bombardment, described by Gaza residents as the most intense of the war, knocked out most communications in the territory and largely cut off the besieged enclave’s 2.3 million people from the world. The military released grainy images showing tank columns moving slowly in open areas of Gaza, many apparently near the border, and said warplanes bombed dozens of Hamas tunnels and underground bunkers. The underground sites are a key target in Israel’s campaign to crush the territory’s ruling group after its bloody incursion into Israel three weeks ago.

The escalation ratcheted up domestic pressure on Israel’s government to secure the release of dozens of hostages seized in the Oct. 7 rampage by Hamas, when militants stormed from Gaza into nearby Israeli towns and gunned down civilians and soldiers. The unprecedented attack during a major Jewish holiday initiated a war between Israel and Hamas that could spread into a broader Mideast conflict.

Desperate family members met with Netanyahu on Saturday and expressed support for an exchange for Palestinian prisoners held in Israel, a swap floated by the top Hamas leader in Gaza.

Netanyahu told the nationally televised news conference that Israel is determined to bring back all the hostages, and maintained that the expanding ground operation “will help us in this mission.” He said he couldn’t reveal everything that is being done due to the sensitivity and secrecy of the efforts.

“This is the second stage of the war, whose objectives are clear: to destroy the military and governmental capabilities of Hamas and bring the hostages home,” he said in his first time taking questions from journalists since the war began.

He didn’t address calls for a cease-fire, but in a speech peppered with references to centuries of Jewish history and military conflicts, made clear his view that Israel’s future depends on its success against “enemy” forces.

“Our heroic soldiers have one supreme goal: to destroy the murderous enemy and ensure our existence in our land. We have always said, ‘Never again,’” he said. “‘Never again’ is now.”

Netanyahu also acknowledged that the Oct. 7 “debacle,” in which more than 1,400 people were killed, would need a thorough investigation, adding that “everyone will have to answer questions, including me.”

The Israeli military said it was gradually expanding its ground operations inside Gaza, while stopping short of calling it an all-out invasion.

“We are proceeding with the stages of the war according to an organized plan,” said the chief military spokesman, Rear Adm. Daniel Hagari. The comments hinted at a strategy of a staged escalation, instead of a massive and overwhelming offensive.

Early in the war, Israel amassed hundreds of thousands of troops along the border. Until now, troops had conducted brief nightly ground incursions before returning to Israel.

Despite the Israeli offensive, Palestinian militants have continued firing rockets into Israel, with the constant sirens in southern Israel a reminder of the threat.

The Palestinian death toll in Gaza rose Saturday to just over 7,700 people since the war began, with 377 deaths reported since late Friday, according to the Gaza Health Ministry. Most of those killed have been women and minors, the ministry said.

Ministry spokesman Ashraf al-Qidra told reporters that the disruption of communications has “totally paralyzed” the health network. Residents had no way of calling ambulances, and emergency teams were chasing the sounds of artillery barrages and airstrikes.

An estimated 1,700 people remain trapped beneath the rubble, according to the health ministry, which has said it bases its estimates on distress calls it received.

Some civilians were using their bare hands to pull injured people from the rubble and loading them into personal cars or donkey carts. In a video posted by local news media, Palestinians sprinted down a street with a wounded man covered in the dust of a building’s collapse. “Ambulance! Ambulance!” the men shouted as they shoved the stretcher into a truck and shouted, “Go! Go!”

Some Gaza residents traveled by foot or car to check on relatives and friends. “The bombs were everywhere, the building was shaking,” said Hind al-Khudary, a journalist in central Gaza and one of a few people with cellphone service. “We can’t reach anyone or contact anyone. I do not know where my family is.”

Israel says its strikes target Hamas fighters and infrastructure and that the militants operate from among civilians, putting them in danger.

The World Health Organization appealed to “the humanity in all those who have the power to do so to end the fighting now” in Gaza. “There are more wounded every hour. But ambulances cannot reach them in the communications blackout. Morgues are full. More than half of the dead are women and children,” it said.

Palestinians say the war also robbed them of the funeral rites that long have offered mourners some dignity and closure. Overcrowded cemeteries have compelled families to dig up long-buried bodies and deepen the holes.

More than 1.4 million people across Gaza have fled their homes, nearly half crowding into U.N. schools and shelters, following repeated warnings by the Israeli military that they would be in danger if they remained in northern Gaza.

A large number of residents have not evacuated to the south, in part because Israel has also bombarded targets in so-called safe zones where conditions are increasingly dire. Food and water supplies were running out. Israel knocked out electricity early in the war.

Humanitarian workers say the trickle of aid Israel has allowed to enter from Egypt in the past week is a tiny fraction of what is needed. Gaza hospitals have been scrounging for fuel to run emergency generators that power incubators and other life-saving equipment.

The U.N. agency for Palestinian refugees, which runs a network of shelters and schools for nearly half the displaced Gaza residents, has lost contact with most staff, spokeswoman Juliette Touma said, and coordinating aid efforts was now “extremely challenging.”

The intensified air and ground campaign raised new concerns about hostages dragged into Gaza. On Saturday, hundreds of relatives gathered in Tel Aviv and demanded that the government put the return of their loved ones ahead of military objectives.

In comments likely to inflame these tensions, Hamas’ top leader in Gaza, Yehiyeh Sinwar, said the Palestinian militant groups “are ready immediately” to release all hostages if Israel releases all Palestinians held in Israeli prisons.

Hagari, the Israeli military spokesman, dismissed the offer as “psychological terror.”

In Cairo, Egyptian President Abdel Fattah el-Sissi said his government was working to de-escalate the conflict through talks with the warring parties to release prisoners and hostages. On Saturday, he spoke with U.N. Secretary-General Antonio Guterres, his office said.

Guterres in a statement said he was “surprised by an unprecedented escalation of the bombardments and their devastating impacts” in Gaza.

Among many, impatience was growing. Turkish President Recep Tayyip Erdogan told hundreds of thousands of people at a pro-Palestinian rally in Istanbul that his country was preparing to proclaim Israel a “war criminal” for its actions in Gaza. He did not give details.

Israel’s foreign minister said he ordered the return of Israel’s diplomatic mission from Turkey to reassess ties.

The overall number of deaths in Gaza and Israel far exceeds the combined toll of all four previous Israel-Hamas wars, estimated at around 4,000.

The conflict has threatened to ignite a wider war across the region. Arab nations — including U.S. allies and ones that have reached peace deals or normalized ties with Israel — have raised increasing alarm over a potential ground invasion.

Magdy reported from Cairo. Associated Press writer Samya Kullab in Baghdad contributed to this report.