"Nothing can justify such assaults on children and such total disregard for human life. The suffering and the shock among children is definitely the worst we have seen," Justin Forsyth, the deputy executive director of UNICEF, said in a statement this week.
Children in besieged eastern Aleppo were due to resume school on Saturday after intense shelling postponed the start of the school year from earlier in September.
Jalal al-Basot, 13, has been out of school for the past two years as conflict has raged in Aleppo, but he registered for the upcoming school year and was hoping to begin as soon as possible.
"In my last year at school I had the highest grades. I don't want to waste my time in the house doing nothing, and I can't even play in the street because of the random raids all over the city," Basot told Al Jazeera.
"So I stay at home, but there is not much electricity or television, so I stick with my old books, reading them again ... I don't care about the bombing if I am in school," he added. "I love school and studying, and I love all subjects. I want to be a maths teacher, as I am obsessed with numbers."
Of the 100,000 children estimated to remain in rebel-held eastern Aleppo, only around half were still attending school, according to Hussein Alhamood, Save the Children's education coordinator for northwestern Syria - and that was even before the recent aerial campaign.
"Most of the public schools [in Aleppo] are destroyed either partially or completely," Alhamood told Al Jazeera.
One in four schools across the country are unusable because of damage or are being used as shelters, according to the United Nations.
As schools have been repeatedly targeted by regime bombs, parents are hesitant about sending their children to school. Many schools have moved underground, and classes are also being held in community centres and private homes, Alhamood said. Save the Children and its local partners support 13 schools in eastern Aleppo, teaching around 3,000 children.
"We don't have public school buildings operating or providing education, as it is a more likely target," he said. "The schools we selected are underground and are likely safer, so the families were happier to send their children there."
The use of bunker buster bombs means there is literally nowhere we can keep children safe, and we want to see the use of these weapons investigated as a potential war crime.
But the ferocity of the latest bombing campaign, which has killed or injured hundreds of children, along with the use of bunker buster bombs - which can explode several metres underground - have threatened the safety of these subterranean schools.
"We're now more likely to see children being pulled from the rubble or treated on the floor of a hospital than sat at a school desk. Children deserve the right to play, to learn, to be children. The use of bunker buster bombs means there is literally nowhere we can keep children safe, and we want to see the use of these weapons investigated as a potential war crime," Nick Finney, Save the Children's country director for northwestern Syria, told Al Jazeera.
"The economic situation in the city is such that people are struggling to find sources for living," he said. "They are sending their children to work in the streets. Children are looking after the families ... Children as young as 15 or 16 are joining armed groups. Their psychology will be affected, across the whole country. We are losing a generation."
Nabeeha Um-Ahmad, the head teacher at the school where Basot was registering last week, told Al Jazeera: "Our children should not be having to live through these horrific circumstances, but they are, and we should do something about that - which is not keeping them locked up at home, increasing their suffering."
Bana al-Abed, aged seven, has been out of school for a year after her school was destroyed in a bombing attack. She has been Tweeting her thoughts on the siege and bombardment of eastern Aleppo, and says that she dreams of one day becoming a teacher herself.
"I miss school, and my friends, so much too - and my teachers. All I want is to go back," she told Al Jazeera.
If the ongoing bombing campaign prevents the resumption of schools on Saturday, Alhamood said that Save the Children would look into launching a system of home education, whereby children would be taught at home or at the home of a teacher - although teachers themselves are hard to come by. Eight of the organisation's teachers have died since the beginning of the year, while thousands more have fled the country.
If children do not resume their studies soon, they will lose out of education, Alhamood said. "We are losing the hope of rebuilding the country."
Source: Al Jazeera