The UN Human Rights Council announced just three days after the initial attack on Israel by terror group Hamas that one of its independent commissions of inquiry had already gathered "clear evidence" of war crimes committed by both sides.
But how are these crimes determined?
Defining war crimes
These crimes are defined as serious violations of humanitarian laws — generally violations against civilians — during a conflict.
"Intentional targeting of civilians and civilian objects without a military necessary reason to do so is a war crime, period," David Crane, an American international law expert and the founding chief prosecutor of the United Nations' Special Court for Sierra Leone, told the Associated Press news agency. "And that's a standard that both sides are held to under international law."
The legal concept of "war crime" is separate from the concepts of "crimes against humanity" or "genocide." While war crimes are restricted to conflicts that occur domestically or between two states, both of the latter can be committed during times of peace too.
Are attacks on civilians always considered war crimes?
In short, no.
"The laws of war do not always protect civilians from death," Mark Kersten of the Munk School of Global Affairs and Public Policy at the University of Toronto told DW in 2022. "Not every civilian death is necessarily illegal." Kersten in the DW interview had described under which conditions and rules of law the killing of civilians would constitute a war crime in the context of the Ukraine war.
The classification of a military act during conflict as a war crime depends on whether the act was justified. So the bombing of a school or residential building may not be considered a war crime if it was deemed militarily necessary.
The difficulty of making this distinction from afar has already arisen in the current conflict: One of the most densely populated areas of the world, Gaza is so crowded that most experts say it is impossible to bomb it without killing some of the 2.2 million civilians who live there. In such circumstances, determining the intended target of an attack is key to determining whether a war crime occurred.
What is the concept of proportionality?
Special courts determine whether a military act is a war crime using three principles: distinction, proportionality and precaution.
Proportionality prohibits armies from responding to an attack with excessive violence. Distinction requires members of the military to constantly try to differentiate between civilians and fighters. Precaution requires that everything possible is done to avoid harming civilians.
Having said that, it is still very difficult to define a war crime.
For example, it may seem clear that Israel's Friday evacuation order to civilians in northern Gaza falls under the "precaution" category. But rights groups, including the United Nations and the International Committee of the Red Cross, say the warning itself breaches international humanitarian law.
"The Israeli military should issue warnings to civilians in Gaza in advance of an attack if doing so would actually allow them to leave safely, and for a safer area," Human Rights Watch program director Sari Bashi wrote in a statement on Friday. "But a warning to flee when there's no safe place to go and no safe way to get there is not an effective warning.”
Jan Egeland, secretary-general of the Norwegian Refugee Council, also called the order illegal, the Associated Press reports.
It is "not an evacuation opportunity, it's an order to relocate. Under humanitarian law, it's called forcible transfer of populations and it's a war crime," he said.
The concept of proportionality is also often debated when it comes to conflicts between Israel and Palestinians.
Some say that in the current conflict, the actions of the Israeli military are justified given the brutality of the Hamas attacks. Others say the Israeli military has gone too far. These are the sorts of questions the ICC is in the process of investigating.
US President Joe Biden said he told Israeli Prime Minister Benjamin Netanyahu on Wednesday, "that it is really important that Israel, with all the anger and frustration and just — I don't know how to explain it — that exists is that they operate by the rules of war, the rules of war. And there are rules of war."
The role of the ICC
The International Criminal Court sits in the Hague in the Netherlands and represents the only permanent international court with the authority to prosecute war crimes, international crimes of genocide and crimes against humanity.
It was established in 2002 in accordance with the Rome Statute. All countries that agree to be party to the statute are then obligated to cooperate with the ICC, and to comply with certain measures, such as providing witness access or evidence and arresting indicted individuals. It also means they are subject to the court's jursidiction.
The ICC recognized Palestine as a member state in 2015. However Israel — like the US, China, Russia and Egypt — is not a member. So although the ICC does have jurisdiction determining war crimes in the current conflict, its decisions have no authority in Israel.
The ICC also has a notoriously difficult time prosecuting war crimes even when they're committed by countries that are party to the Rome Statute. The court has only won a handful of convictions over the two decades of its existence.
Edited by: Kate Hairsine