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.
