Thirteen-year-old Tasneem al-Nahal lies in the morgue of Gaza City's Shifa hospital, dressed in the pink-and-blue tracksuit she was wearing when an Israeli air raid killed her.

A few hours earlier, she was by the sea, playing with neighbours under a brilliantly blue sky.

But when the air strike hit, pieces of shrapnel pierced her skull, spilling her bright red blood onto the pavement in front of her house.

The six-day conflict between Israel and Gaza militant groups has claimed the lives of at least 23 children, according to the Palestinian Centre for Human Rights, innocents cut down in a battle they barely understand.

Hundreds more have been injured. And for those children who escape the physical toll of the war, there is a heavy psychological price to be paid.

Many are traumatised by what they see and hear, terrified of a relentless air campaign, and unable to process the violence and death that surrounds them.

In Gaza City's Sheikh Radwan neighbourhood, just before noon, a funeral procession moves towards a mosque, where prayers will be said over the bodies of the Dallu family.

At least eight members of the family were killed in a single strike on Sunday, the deadliest of the conflict so far.

The bodies of the Dallu children, wrapped in Palestinian flags, their greying faces exposed, are carried by relatives at the head of a chanting crowd of men and boys.

"Do children fire rockets?" screamed a man through a loudspeaker. "No!" the crowd chanted back.

Inside the mosque, the bodies are laid out while prayers are performed, and curious children try to squeeze between adults to see the corpses.

One wide-eyed boy is pushed back by an adult, who tries to keep him from the macabre scene. On one body, relatives have pinned a photograph of the smiling girl who used to be.

Outside, gangs of children mill around, some holding green Hamas flags they have been given to wave.

As they wait for the prayers to end, a sudden screech fills the air, prompting both children and adults to duck. The sound is of two rockets fired towards Israel, which leave white smoke trails in the sky.

"We don't want the war, it's scary and awful," says 12-year-old Mohammed Radwan shyly. "We want peace, we want a truce.

"When I hear the bombing I get onto the sofa and cover myself with pillows to try to be safe. I try to hide myself as much as possible.

"Sometimes I go over to my mum and hold onto her too," he adds, slapping another boy who teases him for the admission.

Thirteen-year-old Ezzedine Hussein is full of bravado at first, talking over the other boys, glaring with his green-blue eyes.

"We want to say to the Jews: We're not scared, we are defending our land and we want our rights," he says.

But questioned further, he acknowledges the explosions that rumble through Gaza's nights do shake him.

"The war scares us, of course, it's killing children and we see what happens to our friends," he says.

"I do get scared but I try to calm myself down. I pray and I ask God to protect us."

Mohammed's brother, Rushi, who looks younger than the 15 years he claims, says his family knew the Dallus children.

"It's so sad when we see them, it makes me want to cry because I knew them, they were from our area," he says.

Psychologist Hassan Zeyada, who has worked with the Gaza Community Mental Health Programme since 1991, says the territory's children are those most at risk during war.

"All the things that can help adults -- social networks, previous experiences and so on -- are not available to children," he told AFP.

The trauma manifests itself in multiple ways, he says, with children becoming terrified to be left alone, experiencing sleep disorders, becoming aggressive or uncommunicative, and losing the ability to concentrate.

For many of Gaza's children, the current round of violence will be the second war they have lived through, after Operation Cast Lead, the 22-day campaign Israel launched at the end of December 2008 in a bid to stamp out persistent cross-border rocket fire.

"They will re-experience a lot of the trauma they have from the past," he said.

Zeyada's organisation plans to send out crisis intervention teams when the violence is over, but their work, he says, will be difficult.

"The problem here in Gaza is that we are living in a high level of stress and ongoing trauma. No one can guarantee that this will not happen again."