GAZA CITY, Gaza Strip – Tiny bodies lying side by side wrapped in white burial shrouds. The cherubic face of a dead preschooler sticking up from the rubble of her home. A man cradling a wounded boy in a chaotic emergency room after Israel shelled a UN school.

Children, who make up more than half of crowded Gaza's 1.4 million people, are the most defenceless victims of the war between Israel and Hamas. The Israeli army has unleashed unprecedented force in its campaign against Hamas militants, who have been taking cover among civilians.

A photo of four-year-old Kaukab Al Dayah, just her bloodied head sticking out from the rubble of her home, covered many front pages in the Arab world Wednesday. "This is Israel," read the headline in the Egyptian daily Al-Masry Al-Youm. The preschooler was killed early Tuesday when an F-16 attacked her family's four-storey home in Gaza City. Four adults also died.

As many as 257 children have been killed and 1,080 wounded, with about a third of the total casualties since Dec. 27, according to UN figures released today.

Hardest on the children is the sense that nowhere is safe and adults can't protect them, said Iyad Sarraj, a psychologist hunkering down in his Gaza City apartment with his four stepchildren, ages three to 17. His 10-year-old, Adam, is terrified during bombing raids and has developed asthma attacks, Sarraj said.

Israel says it is targeting Hamas in response to its repeated rocket attacks on southern Israel, and is doing its utmost to avoid civilian deaths. However, foreign aid officials note that civilians can't escape blockaded Gaza and that bombing crowded areas inevitably leads to civilian casualties. The Israeli military has used tank and artillery shells, as well as large aerial bombs.

In the Shati refugee camp on the Mediterranean, 10 boys were playing football in an alley today when a shell from an Israeli gunboat hit a nearby Hamas prison.

At the sound of the explosion, one of the older boys whistled, a signal to interrupt the game. Several players took cover with their backs pressed against a wall. After a minute or two, the game resumed.

Samih Hilal, 14, said he sneaked out of his grandfather's house against the orders of his worried father. The house was crowded with relatives who fled more dangerous areas, he said, and he couldn't stand being cooped up for so many hours.

"Do you think we are not afraid? Yes, we are. But we have nothing to do but play," Samih said.

Another boy, 13-year-old Yasser, waved toward the unmanned Israeli drones in a defiant gesture, instead of seeking cover during the shelling. "There is nothing we can do. Even if we run away here or there, their shells are faster than us," he said.

Indeed, all of Gaza has become dangerous ground.

Children have been killed in strikes on their houses, while riding in cars with their parents, while playing in the streets, walking to a grocery and even at UN shelters.

Sayed, Mohammed and Raida Abu Aisheh – ages 12, eight and seven – were at home with their parents when they were all killed in an Israeli air strike before dawn Monday. The family had remained in the ground floor apartment of their three-storey building, while the rest of the extended clan sought refuge in the basement from heavy bombardment of nearby Hamas installations.

Those in the basement survived. The children's uncle, Saber Abu Aisheh, 49, searched today through the rubble, a heap of cement blocks, mattresses, scorched furniture and smashed TVs.

He said Israel gave no warning, unlike two years earlier when he received repeated calls from the Israeli military, including on his cellphone, that a nearby house was going to get hit and that he should evacuate.

"What's going on is not a war, it's a mass killing," said Abu Aisheh, still wearing the blood-splattered olive-coloured sweater he wore the night of the air strike.

The Israeli military did not comment when asked why the Abu Aisheh house was targeted.

In the Zeitoun neighbourhood of Gaza City, medics found four young children next to their dead mothers in a house, according to the Geneva-based International Committee of the Red Cross. "They were too weak to stand up on their own," the statement said.

The Red Cross did not say what happened to the children, but noted that the Israeli army refused rescuers permission to reach the neighbourhood for four days. Israel said the delay was caused by fighting.

Medic Mohammed Azayzeh said he retrieved the bodies of a man and his two young sons from central Gaza on Wednesday. One of the boys, a one-year-old, was cradled in his father's arms.

Loading... Loading... Loading... Loading... Loading... Loading...

In the Jebaliya refugee camp, five sisters from the Balousha family, ages four, eight, 11, 14 and 17, were buried together in white shrouds on Dec. 29. An Israeli air strike on a mosque, presumably a Hamas target, had destroyed their adjacent house. Only their parents and a baby girl survived.

Israel accuses Hamas of cynically exploiting Gaza's civilians and using them as human shields. The military has released video footage showing militants firing mortars from the rooftops of homes and mosques.

"Israel wants to see no harm to the children of Gaza," said Israeli government spokesman Mark Regev. "On the contrary, we would like to see their children and our children grow up without the fear of violence. Until now, Hamas has deliberately prevented that from becoming reality."

Rocket fire from Gaza has disrupted life in Israeli border communities, and with the latest intensified militant attacks, hundreds of thousands of Israelis are in rocket range. Schools are closed and fearful Israeli children rush into bomb shelters at the sound of air raid sirens.

In the ongoing chaos of Gaza, it's difficult to get exact casualty figures. Since Dec. 27, at least 750 Palestinians have been killed, according to Gaza Health Ministry official Dr. Moawiya Hassanain.

Of those, 257 were children, according to the UN's top humanitarian official, John Holmes, citing Health Ministry figures that he called credible and deeply disturbing.

"We are talking about urban war," said Abdel-Rahman Ghandour, the Jordan-based spokesman for UNICEF in the Middle East and North Africa. "The density of the population is so high, it's bound to hurt children ... This is a unique conflict, where there is nowhere to go."

Successive generations of Gaza children have grown up with violence, part of the accelerating conflict with Israel. In the late 1980s, many threw stones at Israeli soldiers in a revolt against occupation. In the second uprising, starting in 2000, some were recruited by Hamas as suicide bombers.

Sarraj, the psychologist, said he fears for this generation. Having experienced trauma and their parents' helplessness, they may be more vulnerable to recruitment by militants.

In his Gaza City apartment, Sarraj tries to reassure his own children.

His 14-year-old stepdaughter lost her school, the American International School, to a recent air strike, and a girlfriend was killed in another attack. The family lives in the middle-class Rimal neighbourhood and still has enough fuel to run a generator in the evenings, enabling the children to read.

Yet when the bombings start, he can't distract them. "They are scared," he said. "They run to find the safest place, in the hallway, away from the window."