"The entrenched impunity that OHCHR (the U.N. rights agency) has reported on for many years cannot persist," High Commissioner for Human Rights Volker Turk said in a report on the situation in Gaza and in the Israeli-occupied West Bank.

He said that this impunity had contributed to violations that could amount to international crimes.

Turk urged all parties to the conflict to "put an end to impunity and conduct prompt, independent, impartial, thorough, effective and transparent investigations" into alleged crimes under international law.

He also called on them to implement a ceasefire on human rights and humanitarian grounds, to ensure full respect for international law, and to ensure accountability for violations and abuses.

Last month, the International Court of Justice (ICJ) in The Hague ordered Israel to prevent acts of genocide against Palestinians and do more to help civilians, although it stopped short of ordering a ceasefire as requested by South Africa, which brought the caethe plaintiff in the case.

In separate proceedings, South Africa on Tuesday urged the court to issue a non-binding legal opinion that the Israeli occupation of Palestinian territories is illegal, arguing it would help efforts to reach a settlement.