The war in Gaza has "ruptured any sense of a shared humanity," the head of the International Committee of the Red Cross said on Saturday.
ICRC head Mirjana Spoljaric called for an urgent ceasefire in Gaza, saying Israel and Hamas must respect international law and protect civilians caught up in their conflict.
She said getting a steady, substantial flow of desperately needed aid into the besieged Palestinian territory - where the United Nations says more than 90 percent of the population is on the brink of famine - was "only part of the solution".
"Alleviating the humanitarian catastrophe in Gaza starts with a clear will and measures that safeguard civilian life and human dignity, meaning both sides must conduct their military operations in a way that spares the civilians who are caught in the middle," Spoljaric said.
"The only way to achieve this is that the parties strictly adhere to international humanitarian law, which means preserving the life, dignity and humanity of all people affected by armed conflict, regardless of which side they are on.
"It is the line between humanity and barbarity," she insisted.
"Preserving civilian life and health is the rule, not the exception."