Truckloads of aid idled at Egypt’s border with Gaza, barred from entry, as residents and humanitarian groups pleaded for water, food and fuel for dying generators, saying the tiny Palestinian territory sealed off by Israel after last week’s rampage by Hamas was near total collapse.

Hospitals were on the verge of losing electricity, threatening the lives of thousands of patients, and hundreds of thousands of Palestinians displaced from their homes searched for bread. Israel maintained punishing airstrikes across Gaza as a ground invasion loomed, while Hamas militants kept up a barrage of rocket attacks — and tensions mounted near the Israel-Lebanon border.

More than a week after Israel cut off entry of any supplies, all eyes were on the Rafah crossing, Gaza’s only connection to Egypt. Mediators were trying to reach a cease-fire that would let in aid and let out trapped foreigners. Israeli airstrikes forced the crossing to shut down last week, and local media reported Israel struck the crossing again on Monday.

Palestinian boys sit on the rubble of a building destroyed in an Israeli airstrike in Nuseirat camp in the central Gaza Strip. Photo / AP

Israel evacuated towns near its northern border with Lebanon, where the military has exchanged fire repeatedly with the Iranian-backed Hezbollah group. US Secretary of State Antony Blinken met with Israel’s defence minister, and US President Joe Biden weighed whether to visit Israel after an invitation from Israeli Prime Minister Benjamin Netanyahu.

Speaking to the Israeli Knesset, Netanyahu warned Iran and Hezbollah, “Don’t test us in the north. Don’t make the mistake of the past. Today, the price you will pay will be far heavier,” referring to Israel’s 2006 war with Hezbollah, which operates out of Lebanon.

Soon after he spoke, the Knesset floor was evacuated as rockets headed toward Jerusalem. Sirens in Tel Aviv warning of incoming rockets prompted US and Israeli officials to take shelter in a bunker, officials said.

This has become the deadliest of the five Gaza wars for both sides. At least 2778 people have been killed and 9700 wounded in Gaza, according to the health ministry there. More than 1400 Israelis have been killed, the vast majority civilians massacred in Hamas’ October 7 assault. The Israeli military said on Monday at least 199 hostages were taken into Gaza, more than previously estimated. Hamas said on Monday it was holding 200 to 250 hostages, including foreigners whom it said it would free when it was feasible.

The head of Israel’s Shin Bet security service, in charge of monitoring militant groups, took responsibility for failing to avert Hamas’ surprise attack. As agency head, “the responsibility for that is on me”, Ronen Bar said.

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 “There will be time for investigation — now is a time for war,” he wrote in a letter to Shin Bet workers and their families.

The combination of airstrikes, dwindling supplies and Israel’s mass evacuation order for the north of the Gaza Strip has thrown the tiny territory’s 2.3 million people into upheaval and increasing desperation. More than one million have fled their homes, and 60 per cent of them are now in the approximately 14-kilometre-long area south of the evacuation zone, according to the UN.

The Israeli military says it is trying to clear away civilians for their safety ahead of a major campaign against Hamas in Gaza’s north, where it says the militants have extensive networks of tunnels and rocket launchers. Much of Hamas’ military infrastructure is in residential areas.

Those fleeing northern Gaza still faced airstrikes in the south. Before dawn on Monday, a strike in the town of Rafah collapsed a building sheltering three families who had evacuated from Gaza City. At least 12 people were killed and nine others remained buried under rubble, survivors from the families said. The strike reduced the house to a vast crater blanketed with wreckage.

Wounded Palestinians arrive at al-Shifa Hospital following Israeli airstrikes on Gaza City in the central Gaza Strip. Photo / AP

Hospitals are expected to run out of generator fuel in the next 24 hours, meaning life-saving equipment like incubators and ventilators will stop functioning, the UN said. Thousands of patients’ lives were at risk, the UN said.

People grew increasingly desperate in their search for food and water. With taps dry, many have resorted to drinking dirty or sewage-filled water, risking the spread of disease.

More than 400,000 displaced people in the south crowded into schools and other facilities of the UN agency for Palestinians, UNRWA. But the agency can’t provide them with any supplies. UNRWA said it has only one litre of water a day for each of its staff members trapped in the territory.

“Gaza is running out of water, and Gaza is running out of life,” said UNRWA chief Philippe Lazzarini, calling for a lifting of the siege. “We need this now.”

The few operating bakeries had long snaking lines of people. Ahmad Salah in the city of Deir al-Balah said he waited 10 hours to get a kilogram of bread to feed 20-30 family members.

In northern Gaza, unknown numbers remained, either unwilling or unable to leave.

UNRWA said 170,000 people were sheltering at its schools in the north when the order to leave came. But it couldn’t evacuate them and doesn’t know if they remained. More than 40,000 have crowded together on the grounds of Gaza City’s al-Shifa Hospital and surrounding streets, hoping it will be safe from bombardment.

Hamas urged people to ignore the evacuation order. The Israeli military on Sunday released photos it said showed a Hamas roadblock preventing traffic from moving south.

Doctors and many hospital staff have refused to evacuate, saying it would mean death for critically ill patients and newborns on ventilators.

The medical aid group Doctors Without Borders said many of its personnel decided to stay in the north to treat the wounded. They had run out of painkillers, and staff reported “wounded screaming in pain”, it said.

Israel has said the siege won’t be lifted until Hamas releases all the captives. The country’s water ministry said water had been restored at one “specific point” in Gaza, outside the southern town of Khan Younis, but aid workers in Gaza said they had not yet seen evidence the water was back.

On the Gaza side of the Rafah crossing, crowds of Palestinians with dual citizenship waited anxiously, sitting on suitcases or crouched on the floor, some comforting crying infants.

“They are supposed to be a developed country, talking about human rights all the time,” Shurouq Alkhazendar, whose two kids are American citizens, said of the United States. “You should protect your citizens first, not leave them all alone suffering and being humiliated in front of the crossing.”

After increasing cross-border exchanges with Hezbollah in the north, the Israeli military ordered residents to evacuate 28 communities within two kilometres of the Lebanese border.

“Israel is ready to operate on two fronts, and even more,” said Rear Admiral Daniel Hagari, a military spokesman.

Hezbollah released video footage showing snipers shooting out cameras at several Israeli army posts along the border, apparently to prevent Israel from monitoring movements on the Lebanese side.

The US government began evacuating some 2500 American citizens by ship from the Israeli port city of Haifa to Cyprus. Commercial airlines have largely stopped flying into Israel’s Ben-Gurion International Airport.

Blinken returned to Israel for a second time in less than a week after a six-country tour through Arab nations aimed at preventing the fighting from igniting a broader conflict.

Israeli forces, supported by a growing deployment of US warships in the region and the call-up of some 360,000 reservists, have positioned themselves along Gaza’s border and drilled for what Israel said would be a broad campaign to dismantle Hamas. Israel said it has already struck dozens of military targets, including command centres and rocket launchers, and also killed Hamas commanders.