Geneva: Deadly Israeli air strikes on the Gaza Strip's largest refugee camp "could amount to war crimes", the UN Human Rights Office said on Wednesday.
Israeli strikes have targeted the Jabalia refugee camp twice in two days, killing and wounding dozens, according to the health ministry in the Hamas-run Palestinian territory.
Israel said Tuesday's raid was a successful hit on top Hamas commander Ibrahim Biari.
"Given the high number of civilian casualties & the scale of destruction following Israeli air strikes on Jabalia refugee camp, we have serious concerns that these are disproportionate attacks that could amount to war crimes," the office wrote on X, formerly Twitter.
Israel has relentlessly pounded Gaza in retribution for the worst attack in the country's history.
Hamas gunmen stormed across the border from Gaza on October 7, killing 1,400 people, mostly civilians, and taking more than 230 hostages, according to Israeli officials.
Israel's retaliatory bombing campaign has killed 8,796 people, mainly women and children, according to Hamas-run Gaza's health ministry.
The principle of proportionality referred to by the UN plays a central role in the wars of law defined by the Geneva Conventions.
Civilians and civilian structures must be spared - but the death of civilians during a conflict does not necessarily constitute a war crime.
Warring parties can launch attacks deemed proportionate on military targets even while knowing that civilians could also be hit.
A crime is committed when an attack is deliberately carried out against civilians, or if the scale of the damage to civilians is excessive compared to the military advantage.
The International Criminal Court is the only independent international legal authority that carries out investigations into genocide, war crimes and crimes against humanity, but Israel is not a member.
AFPTV images from Wednesday's strike on the camp showed extensive damage and rescuers clawing through rubble to extract blood-stained casualties.
The large death toll from the strikes has drawn a chorus of international condemnation, with Bolivia severing diplomatic ties with Israel in protest.
Jordan recalled its ambassador to Israel "to condemn the Israeli war that is killing innocent people in Gaza".
UN chief Antonio Guterres is "appalled over the escalating violence in Gaza, including the killing of Palestinians, including women and children in Israeli air strikes in residential areas of the densely populated Jabalia refugee camp", his spokesman Stephane Dujarric said Wednesday.