The International Court of Justice, the United Nations’ highest judicial body, will begin hearings this week in a case brought by South Africa that accuses Israel of committing genocide in the Gaza Strip.

The hearings, the first step in a lengthy process should the case go forward, will be the first time that Israel has chosen to defend itself, in person, in such a setting, attesting to the gravity of the indictment and the high stakes for its international reputation and standing.

Genocide, the term first employed by a Polish lawyer of Jewish descent in 1944 to describe the Nazis’ systematic murder of about 6 million Jews and others based on their ethnicity, is among the most serious crimes of which a country can be accused.

In its submission to the court, South Africa cited that lawyer, Raphael Lemkin, to expand the definition of genocide. South Africa, whose post-apartheid government has long supported the Palestinian cause, accused Israel of actions in Gaza against Hamas that are “genocidal in character.” It says Israel has killed Palestinian civilians, inflicted serious bodily and mental harm, and created for the residents of Gaza “conditions of life calculated to bring about their physical destruction.”

More than 23,000 Palestinians have been killed over the past three months, a majority of them women and children, according to health officials in Gaza. And most of the enclave’s 2.2 million residents have been displaced since the war began, increasing the danger of disease and hunger, according to international organizations.

The allegation, which Israel categorically denies, is laden with a particular significance in Israel, a country founded in the wake of the near wholesale destruction of European Jewry and that soon after became a haven for Jews expelled by the hundreds of thousands from Arab lands.

Israel, a signatory to the 1948 international Convention against Genocide, is keeping the details of its defense for the court. But Israeli leaders say South Africa’s allegations pervert the meaning of genocide and the purpose of the convention. A more fitting case, they say, could be brought against Hamas, an internationally labeled terrorist organization that is the target of Israel’s military campaign in Gaza.

The International Court of Justice adjudicates disputes between states, and the initial hearings in the Israel case will take place Thursday and Friday in The Hague.

This article originally appeared in The New York Times.