A legal battle over whether Israel’s war against Hamas in Gaza amounts to genocide opens Thursday at the United Nations’ top court with preliminary hearings into South Africa’s call for judges to order an immediate suspension of Israel’s military actions. Israel stringently denies the genocide allegation.

The case, that is likely to take years to resolve, strikes at the heart of Israel’s national identity as a Jewish state created in the aftermath of the Nazi genocide in the Holocaust. It also involves South Africa’s identity: Its ruling African National Congress party has long compared Israel’s policies in Gaza and the West Bank to its own history under the apartheid regime of white minority rule, which restricted most Blacks to “homelands” before ending in 1994.

Israel normally considers U.N. and international tribunals unfair and biased. But it is sending a strong legal team to the International Court of Justice to defend its military operation launched in the aftermath of the Oct. 7 attacks by Hamas.

“I think they have come because they want to be exonerated and think they can successfully resist the accusation of genocide,” said Juliette McIntyre, an expert on international law at the University of South Australia.

In a statement after the case was filed, the Palestinian Authority’s foreign ministry urged the court to “immediately take action to protect the Palestinian people and call on Israel, the occupying power, to halt its onslaught against the Palestinian people, in order to ensure an objective legal resolution.”

Two days of preliminary hearings at the International Court of Justice begin with lawyers for South Africa explaining to judges why the country has accused Israel of “acts and omissions” that are “genocidal in character” in the Gaza war and has called for an immediate halt to Israel’s military actions.

Thursday’s opening hearing is focused on South Africa’s request for the court to impose binding interim orders including that Israel halt its military campaign. A decision will likely take weeks.

Israel’s offensive has killed more than 23,200 Palestinians in Gaza, according to the Health Ministry in Hamas-run Gaza. About two-thirds of the dead are women and children, health officials say. The death toll does not distinguish between combatants and civilians.

In the Oct. 7 attack, in which Hamas overwhelmed Israel’s defenses and stormed through several communities, Palestinian militants killed some 1,200 people, mainly civilians. They abducted around 250 others, nearly half of whom have been released.