The chief prosecutor of the International Criminal Court (ICC) has applied for arrest warrants for Israeli Prime Minister Benjamin Netanyahu and Hamas's leader in Gaza Yahya Sinwar for war crimes.
Karim Khan KC said there were reasonable grounds to believe that both men bore criminal responsibility for war crimes and crimes against humanity from the day of Hamas's attack on Israel on 7 October onwards.
Israeli defence minister Yoav Gallant and Hamas's political leader Ismail Haniyeh, along with the group's military chief Mohammed Deif are also wanted for arrest.
The ICC, based in The Hague, has been investigating Israel's actions in the occupied territories for the past three years - and more recently the actions of Hamas as well.
Mr Netanyahu recently called the prospect of senior Israel figures joining the ICC's wanted list "an outrage of historic proportions".
ICC judges will now decide whether they believe the evidence is sufficient to issue arrest warrants - something which could take weeks or months.
Mr Khan accused the Hamas leaders of having committed crimes including extermination, murder, hostage taking, rape and sexual violence, and torture.
"The crimes against humanity charged were part of a widespread and systematic attack against the civilian population of Israel by Hamas and other armed groups," he said in a statement.
"Some of these crimes, in our assessment, continue to this day."
Hamas, he said, had inflicted "unfathomable pain through calculated cruelty and extreme callousness".
He said Israeli Prime Minister Benjamin Netanyahu and his defence minister Benny Gantz were suspected of crimes including starvation of civilians as a method of warfare, murder, intentionally directing attacks against a civilian population, and extermination.
Mr Khan said his office had evidence that Israel had "intentionally and systematically deprived the civilian population in all parts of Gaza of objects indispensable to human survival".
Israel, he said, has a right to defend itself but not by "intentionally causing death, starvation, great suffering, and serious injury to body or health of the civilian population" which he said were criminal acts.
Israeli war cabinet minister Benny Gantz - a political rival of Mr Netanyahu - denounced the prosecutor's decision.
"Drawing parallels between the leaders of a democratic country determined to defend itself from despicable terror to leaders of a blood-thirsty terror organisation is a deep distortion of justice and blatant moral bankruptcy," he said.
