"The deaths of children on all sides constitute further tragic evidence of the terrible impact the conflict is having on children and their families on all sides," Xinhua quoted the UNICEF as saying in a statement.
The death of a four-year-old Israeli child in a rocket attack Friday and the reported deaths of two Palestinian children in Gaza in an airstrike Saturday morning, add to those of 478 other Palestinian children killed in attacks in Gaza over the last month, according to the statement.
"Children are bearing the brunt of a conflict that is not of their making," it said. "The fighting is inflicting terrible suffering on children and having a devastating impact on the infrastructure upon which they rely for their health, education, protection and wellbeing."
The UN agency called on all parties to the conflict to "protect civilians, especially children, as required by international law and to recommit to a ceasefire so that no further lives are lost and humanitarian agencies can expand their essential work in Gaza".
Israel and Hamas resumed the fighting earlier this week after the indirect negotiations in Cairo, aiming at achieving ceasefire in the hostility that began July 8, had collapsed Tuesday.
At least 2,042 Palestinians, the majority of them civilians, have been killed in the conflict, along with 66 Israelis, according to figures cited by the UN Office for the Coordination of Humanitarian Affairs (OCHA).
In addition, some 460,000 people are seeking shelter either in UN Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) facilities, government shelters or with host families.