Judges at the International Court of Justice on Thursday opened two days of legal arguments in a case filed by South Africa accusing Israel of genocide in its Gaza war. Israel rejects the allegation.

The conflict between Israel and Hamas has led to accusations of war crimes on both sides, as combatants are bound by international humanitarian law to minimize the impact on civilians.

"For the first time in history, nuclear weapons are going to be illegal in international law," says Elayne Whyte, who oversaw the treaty's creation.