With over 20,000 killed by Israel over two years, Gaza's children are paying the heaviest price of its ongoing genocide in the Palestinian territory.

The U.N.'s children's body, UNICEF on Tuesday decried the grave price paid by innocent children in Gaza, calling on Israel to declare an immediate cease-fire to end what it called an "unprecedented" violence in the besieged enclave.

"For nearly two years now, children have paid the heaviest price in this crisis," UNICEF spokesperson Ricardo Pires said in Geneva.

He added that "an average of one child (is) either killed or maimed every 17 minutes," calling the figure "unacceptable" and "staggering."

Pires, on the second anniversary of the Israeli war, stressed that children are enduring severe physical and psychological trauma, having been orphaned or displaced multiple times, and exposed to "horrors that no child should ever have to look at or live."