Israeli forces have stepped up their assault on Gaza City with a wave of heavy air strikes, marking a sharp escalation from previous military operations.

Unlike earlier phases of the war, the current offensive has relied heavily on aerial bombardments, with entire apartment blocks and large concrete structures reduced to rubble.

The intensification of strikes in recent days has triggered a surge in civilian displacement.

Israel has warned all residents of Gaza City to leave immediately in anticipation of a huge ground offensive.

On Sunday, the Israeli Defense Forces (IDF) said about 250,000 people had left the city and moved south. It also said it had destroyed a high-rise building that it said had been used “to advance and execute terrorist attacks” against its troops.

Israeli Prime Minister Benjamin Netanyahu says the city is Hamas’s last major stronghold. But the plan to occupy Gaza City has brought international criticism.

The UN has warned an intensification of the offensive on an area where a famine has already been declared will push civilians into an “even deeper catastrophe”. Gaza City is the largest urban centre in the territory and a historic heart of Palestinian political and social life.

Residents say the Israeli military has been targeting schools and makeshift shelters, often issuing warnings only moments before bombardments.

Many families have been forced to flee in darkness toward western Gaza.

“We escaped certain death, my husband, our three children and I,” said Saly Tafeesh, a mother sheltering in the city. “My brother died in my arms after being shot by a quadcopter drone. We ran in the dark to the west of Gaza.”

The Israeli military has told residents to evacuate to the south of the territory – but many families say they cannot afford the journey, which costs up to $1,100 (£800). Hamas, meanwhile, has intensified its calls for residents to stay put and resist leaving the city.

Rubein Khaled, a father-of-nine preparing to move south, expressed frustration.

“The Hamas preacher at Friday prayers accused anyone leaving Gaza City of being a coward running from the battlefield,” he said.

“But why doesn’t he tell Hamas leaders to surrender and release the Israeli hostages so this war can stop? We don’t want to leave either, but we have no choice.”

Israeli forces have not yet reached some eastern neighbourhoods that have remained largely intact since earlier raids in January, but the current campaign suggests they may now be seeking to dismantle entire districts.

Meanwhile, a Qatari foreign ministry spokesman strongly criticised Israel’s prime minister in an interview with the BBC following this week’s Israeli strike on Hamas officials in the Qatari capital Doha.

Foreign Ministry spokesman Majed Al-Ansari told the BBC that the international community had “to deal with a Netanyahu problem”.

“He is not somebody who is listening to anybody right now, who is listening to any reason, and we have to collectively stop him in his tracks,” the official said.

He argued the strike in Doha showed the Israeli leader “never intended to sign any peace deal” to end the war in Gaza and instead “believes he can re-shape the Middle East in his own image”.

Five of the group’s members and a Qatari security officer were killed in Tuesday’s strike – though the Palestinian armed group claimed no senior leaders had been killed. Hamas members had been in Doha to discuss the latest US proposal for a ceasefire in Gaza.

Israel has faced widespread condemnation, including at the UN Security Council. Benjamin Netanyahu said Israel targeted the “terrorist masterminds” behind the 7 October 2023 Hamas attack on Israel.

Qatar’s Prime Minister Mohammed bin Abdulrahman al-Thani earlier said that Qatar did not get advance warning of the strike, only receiving a call from a US official 10 minutes after the attack had started.

On Friday, al-Thani had dinner with US President Donald Trump and his envoy Steve Witkoff in New York, having earlier met Vice President JD Vance and Secretary of State Marco Rubio at the White House.

Rubio is travelling to Israel this weekend in a show of solidarity with Israel ahead of a UN meeting later this month at which France and the UK are expected to formally recognise a Palestinian state.

On Sunday, the Hamas-run health ministry in Gaza said the bodies of 47 people killed by the Israeli military had arrived at its hospitals over the previous day.

Since UN-backed global food security experts confirmed a famine in Gaza City on 22 August, the ministry has reported that at least 142 people have died from starvation and malnutrition across the territory. Israel has said it is expanding its efforts to facilitate aid deliveries and has disputed the health ministry’s figures on malnutrition-related deaths.

The Israeli military launched its campaign in Gaza in response to the Hamas-led attack on southern Israel on 7 October 2023, in which about 1,200 people were killed and 251 others were taken hostage.

At least 64,803 people have been killed in Israeli attacks in Gaza since then, according to the territory’s health ministry.