"I will never forget the utter shock on these kids' faces - they thought they were safe in a UN school," Correspondent Dan Rivers said.
In between the bandages, I could see the soreness of Randa’s skin. Her eyes stare out at a world which has been brutal to her.
An Israeli student has started an online campaign in an attempt to encourage respect between Jews and Arabs.
The Israelis are not admitting responsibility but they are not denying it either.
An Israeli military spokesman told ITV News that there was an "extensive battle in the area" around the school today, as Israeli soldiers responded to Hamas' anti-tank missiles and mortars.
He said Israel had had yet to determine whether it was Israeli ordinates or Hamas ordinates that struck the school - but if it was the Israelis it was a mistake.
The UN Secretary-General Ban Ki-moon said today his staff in Gaza had been trying to arrange an evacuation.
Israel said it had been urging an evacuation over the last three days, but had no idea why the evacuation did not happen.
So something that was agreed in principle didn't happen in practice, and I'm afraid the cost in that has been very high indeed.
An attack on a UN-run school in Gaza "underscores the need to end the violence", a spokesperson for US Secretary of State John Kerry said.
At least 16 people - including women and children - were killed in the shelling.
UN Secretary-General Ban Ki-moon has condemned the incident, blaming a "massive Israeli assault" for the atrocity.
UN Secretary-General Ban Ki-moon said he is "appalled" by an attack on a school in Gaza which has killed at least 16 people.
The UN-run school was sheltering Palestinians at the time of the shelling, which Ban blamed on a "massive Israeli assault".
"Circumstances are still unclear. I strongly condemn this act. Many have been killed - including women and children, as well as U.N. staff," Ban said in a statement.
"Throughout the day, our staff had been attempting to arrange a humanitarian pause in the hostilities so that civilians could be evacuated.
"I express my profound condolences to the families of the victims and those of so many hundreds of innocent Gazans who have tragically been killed as a result of the massive Israeli assault."
A woman who lost her son in an attack on a UN-run school in Gaza said there as "blood and screams" as shells hit the facility.
ITV News witnessed the aftermath of the attack at the Beit Hanoun elementary school, which was being used to shelter Palestinians from the heavy violence.
Laila Al-Shinbari said families had gathered to await evacuation when the shelling began.
"All of us sat in one place when suddenly four shells landed on our heads ... Bodies were on the ground, (there was) blood and screams. My son is dead and all my relatives are wounded including my other kids," she told Reuters.
Nowhere is currently safe for children in Gaza, Unicef has said after a UN-run school was hit by shelling - leaving at least 16 people dead.
"There is nowhere safe for children and their families in Gaza right now," Pernille Ironside, head of Unicef's office in Gaza, said.
"There are lasting emotional and physical scars that children are bearing across Gaza Strip.
"I saw four-year-old Shima in the hospital the other day, and she was longing for her mother and her siblings, all of whom died as they were seeking shelter, leaving their home in search of a safer place, and only Shima and her father survived."
A ceasefire is needed so people in desperate need of humanitarian aid can be reached, the organisation added.
Families living in a UN-run school were about to be evacuated by the Red Cross when the facility was attacked, a father has told ITV News at a hospital in Gaza.
The school in Beit Hanoun was sheltering Palestinians from the ongoing violence in the region, which has claimed the lives of 700 Palestinians.
ITV News Correspondent Dan Rivers reports:
One father of six told me they were waiting to be evacuated by the Red Cross when the shells started falling #Gaza
Foreign Secretary Philip Hammond has said Hamas must agree to a humanitarian ceasefire without conditions.
Hamas leader Khaled Meshaal said he was ready to accept a halt to the violence, but only if Israel ended its siege in Gaza.
His comments come as at least 16 people were killed in an attack on a UN school in Gaza.
The Israeli military has told ITV News that Hamas rockets may have hit a school in Beit Hanoun where over a dozen fatalities have been reported.
A UN spokesman in Gaza earlier accused Israeli defence forces of attacking the school, despite having been given the exact co-ordinates of the facility.
ITV News Senior International Correspondent John Irvine reports:
IDF tell #ITVnews Hamas rockets landed in Beit Hanoun in Gaza, possibly hitting UN school where 15 at least killed
At least 16 people have been killed after a reported Israeli attack on a UN school in the northern Gaza strip, local media reports.
The school was being used to shelter hundreds of people from the ongoing violence in the region.
ITV News witnessed children "lying in pools of blood" in the aftermath of the shelling.
Scattered books and belongings were seen scattered across courtyard within the facility.