What is the International Court of Justice and why is it weighing in on humanitarian aid in Gaza?

The top United Nations court on Monday will begin hearing from 40 countries on what Israel must do to provide desperately needed humanitarian assistance to Palestinians in Gaza and the occupied West Bank.

Last year, the U.N. General Assembly asked the International Court of Justice to weigh in on Israel's legal obligations after the country effectively banned the U.N. agency for Palestinian refugees, the main provider of aid to Gaza, from operating. The United States, Israel's closest ally, voted against the resolution.

Israel over a month ago again cut off all aid to Gaza and its over 2 million people. Israel has disputed that there is a shortage of aid in Gaza, and says it is entitled to block the aid because it says Hamas seizes it for its own use.

The Hague-based court has been asked to give an advisory opinion, a non-binding but legally definitive answer, in the latest judicial proceedings involving Israel and the 18-month war in Gaza. That is expected to take several months.

What is the International Court of Justice? Set up in the aftermath of World War II, the ICJ is an organ of the U.N. and adjudicates disputes between countries. Certain U.N. bodies, including the General Assembly, can request advisory opinions from the court's 15 judges.

All 193 U.N. member states are members of the ICJ, though not all of them automatically recognize its jurisdiction.

Last year, the court issued an unprecedented and sweeping condemnation of Israel's rule over the occupied Palestinian territories, finding Israel's presence unlawful and calling for it to end. The U.N. General Assembly sought the opinion after a Palestinian request. The ICJ said Israel had no right to sovereignty in the territories, was violating international laws against acquiring territory by force and was impeding Palestinians' right to self-determination.

Two decades ago, the court in another advisory opinion held that Israel was violating international law by constructing a barrier between Israel and the West Bank. That opinion, also requested by the U.N. General Assembly, dismissed Israeli arguments that the wall was needed for security.

Israel has not participated in previous advisory opinion hearings but has submitted written statements.

What is the genocide case that Israel is facing at the ICJ? South Africa went to the court last year to accuse Israel of genocide over its actions in the war in Gaza, which began when Hamas-led militants attacked southern Israel on Oct. 7, 2023, killing about 1,200 people, mostly civilians, and abducting 251.

Israel's retaliatory offensive has killed over 51,000 Palestinians, according to Gaza's Health Ministry, which does not say how many are civilians or combatants. The offensive has reduced much of Gaza to rubble, and most of its people remain homeless.

Israel rejects South Africa's claim and accuses it of providing political cover for Hamas.

South Africa also asked judges to make nine urgent orders known as provisional measures. They are aimed at protecting civilians in Gaza while the court considers the legal arguments.

The court has ruled several times on that request, including ordering Israel to do all it can to prevent death, destruction and any acts of genocide in Gaza. The proceedings are ongoing and likely to take years to reach a conclusion.

How is the ICJ different from the International Criminal Court? The International Criminal Court was established in 2002 as the court of last resort to prosecute those responsible for the world's most heinous atrocities: war crimes, crimes against humanity, genocide and the crime of aggression.

While the ICJ deals with disputes between two or more countries, the ICC seeks to hold individuals criminally responsible.

In November, a three-judge panel issued arrest warrants for Israeli Prime Minister Benjamin Netanyahu, former Defense Minister Yoav Gallant and Hamas' military chief, Mohammed Deif, accusing them of crimes against humanity in connection with the war in Gaza.

The warrants said there was reason to believe Netanyahu and Gallant have used "starvation as a method of warfare" by restricting humanitarian aid and intentionally targeted civilians in Israel's campaign against Hamas, charges Israeli officials deny.

The warrant marked the first time a sitting leader of a major Western ally has been accused of war crimes and crimes against humanity by the global court of justice and has sparked major pushback from supporters of Israel, including the U.S.

Israel and its top ally, the United States, are not members of the court. However, Palestine is, and judges ruled in 2021 that the court had jurisdiction over crimes committed on Palestinian territory.