The group said in a report on Monday, “It is nearly impossible to collect and verify information under the current conditions in Gaza but at least 17,000 children are believed to be unaccompanied and separated and approximately 4,000 children are likely missing under the rubble, with an unknown number also in mass graves”.

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Since October 7, Israel has killed more than 14,000 children in Gaza while others are suffering from severe malnutrition and do not “even have the energy to cry”, the United Nations Children’s Fund (UNICEF), said in a report earlier this year.

The Save the Children report says, “Since October, Gaza has faced relentless violence which has killed over 37,000 people, including thousands of children. It follows an attack in Israel by Palestinian armed groups that killed over a thousand people, including at least 33 children.”

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It also notes that about 250 Palestinian children are also missing in the occupied West Bank, as of 9 June.

Jeremy Stoner, Save the Children’s regional director for the Middle East, has called for an independent investigation into the situation surrounding Gaza’s missing children, and for accountability.

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“Families are tortured by the uncertainty of the whereabouts of their loved ones. No parent should have to dig through rubble or mass graves to try and find their child’s body. No child should be alone, unprotected in a war zone. No child should be detained or held hostage,” he added.

Khaled Quzmar, the general director of the child rights organisation Defense for Children International Palestine, told Al Jazeera that the impact that they have witnessed in the conflict in Gaza is at a level previously unseen, even during the second world war.

“It is a war against children. Children in Gaza are the big cost of the Israeli genocide in Gaza,” Quzmar said.

International criticism has mounted amid the growing death toll in the war, as well as the deteriorating humanitarian crisis.

However, on Sunday, Israeli Prime Minister Benjamin Netanyahu reiterated that he would not agree to any deal that stipulated an end to Israel’s war on Gaza.