THE HAGUE (Reuters) - The International Court of Justice is holding hearings this week in a case brought by South Africa accusing Israel of genocide in the Gaza war and seeking an emergency halt to its Rafah offensive.

WHAT IS THE ICJ?

The ICJ, also called the World Court, is the highest United Nations legal body, established in 1945 to deal with disputes between states. It should not be confused with the treaty-based International Criminal Court, also in The Hague, which handles war crimes cases against individuals.

The ICJ's 15-judge panel - which is expanded by an additional judge of Israel's choosing in this case because there is already a South African judge - deals with border disputes and increasingly cases brought by states accusing others of breaking U.N. treaty obligations.

South Africa and Israel are signatories to the 1948 Genocide Convention giving the ICJ jurisdiction to rule on disputes over the treaty. While the case revolves around the Israeli-occupied Palestinian territories, Palestinians have no official role in the proceedings.

All states that signed the Genocide Convention are obliged to not commit genocide, and to prevent and punish it. The treaty defines genocide as "acts committed with intent to destroy, in whole or in part, a national, ethnical, racial or religious group".

WHAT IS SOUTH AFRICA'S CASE?

The 84-page initial filing, brought by South Africa three months into the war, says that by killing Palestinians in Gaza, causing them serious mental and bodily harm and creating conditions on life "calculated to bring about their physical destruction", Israel is committing genocide against them.

In hearings in January, South Africa focused on Israel's failure to provide essential food, water, medicine, fuel, shelter and other humanitarian assistance to Gaza during its war with Palestinian militant group Hamas.

It also referred to Israel's sustained bombing campaign which Gaza health authorities say has killed over 35,000 people.

WHAT IS ISRAEL'S RESPONSE?

Israeli Prime Minister Benjamin Netanyahu has dismissed the genocide accusations as outrageous. Israel says it does what it can to protect Palestinian civilians in Gaza and accuses Hamas of using Palestinians as human shields, an accusation Hamas denies.

Israel says it must have the right to defend itself after the Oct. 7 Hamas-led attack on Israel in which 1,200 people were killed and 253 abducted, according to Israeli tallies.

WHAT HAS THE ICJ RULED IN THE CASE SO FAR?

After a first round of hearings on emergency measures in January, the court found it was plausible Israel violated some rights guaranteed to Palestinians in Gaza under the Genocide Convention.

Judges ordered Israel to refrain from acts that could fall under the Genocide Convention and ensure its troops commit no genocidal acts against Palestinians.

Under the Genocide Convention, acts of genocide include killing members of a group, causing them serious bodily or mental harm, and deliberately inflicting conditions of life calculated to bring about the destruction of the group in whole or in part.

Judges also ordered Israel to take action to improve the humanitarian situation in Gaza.

In March, the court issued further emergency measures and ordered Israel to take all the necessary and effective action to ensure basic food supplies for Palestinians in Gaza.

WHY MORE EMERGENCY MEASURES HEARINGS?

On May 10, the court announced South Africa had asked for additional emergency measures related to Israel's offensive on Rafah in southern Gaza, where more than a million Palestinians have sought shelter.

South Africa wants the court to order a halt to the military operation in Rafah and Israel to allow unimpeded access to Gaza for U.N. officials, organisations providing humanitarian aid, and journalists and investigators.

In hearings on Thursday and Friday, South Africa and Israel each have two hours to make their case on the new request for emergency measures.

There will be no witness testimony and no cross-examinations. The presentation will be mostly legal arguments brought by state officials and lawyers.

Getting emergency measures is a first step in the wider genocide case that will take several years to complete. Formally called provisional measures, they are meant as a kind of restraining order to prevent a dispute worsening while the court looks at the full case.

A decision on the additional measures is expected in coming weeks.

The ICJ's rulings are final and without appeal, but the ICJ has no way of enforcing them. A ruling against Israel could hurt the country's international reputation and set a legal precedent.

(Reporting by Stephanie van den Berg; Editing by Anthony Deutsch and Timothy Heritage)

By Stephanie van den Berg