Explained | What war crimes laws apply to the Israel-Palestinian conflict?

The Hague: War between Israel and Palestinian militants since the cross-border attack by Gaza's ruling Islamist group Hamas on Oct. 7 has caused a large civilian death toll.

The conflict falls under a complex international system of justice that has emerged since World War Two, much of it aimed at protecting civilians. Even if states say they are acting in self-defence, international rules regarding armed conflict apply to all participants in a war.

What laws govern the conflict?

Internationally accepted rules of armed conflict emerged from the 1949 Geneva Conventions, which have been ratified by all United Nations member states and supplemented by rulings at international war crimes tribunals.

Treaties govern the treatment of civilians, soldiers and prisoners of war in a system collectively known as the "Law of Armed Conflict" or "International Humanitarian Law". It applies to government forces and organised, non-state armed groups, which would include Hamas militants.

Can hospital be a military target?

Israel has been criticized for targeting medical facilities in Gaza, including the main Al Shifa hospital in Gaza City. It has long accused Hamas of setting up command and control centres beneath medical facilities in an effort to avoid air strikes. Hamas denies this.

The World Health Organization said as of Nov. 15, 152 attacks on health infrastructure had been verified in Gaza.

There are many examples of attacks on health facilities in conflict zones in recent decades, from Ukraine and Afghanistan to Yemen and Syria, but the most recent jurisprudence dates to trials dealing with the Balkan wars of the 1990s.

Canadian lawyer Carolyn Edgerton, who worked on several cases at the International Criminal Tribunal for the former Yugoslavia in The Hague, said while they did not examine hospital attacks specifically, the jurisprudence stressed the need to balance the principles of military necessity and humanity.

"Attacking hospitals and other medical units is prohibited under the first Geneva Convention, and that protection extends to the wounded and the sick, the staff of those establishments and ambulances. And that protection doesn't end unless those establishments are used by a party to the conflict to commit an act ... harmful to the enemy," she said.

Defining what is "harmful to the enemy" is itself the focus of an ongoing legal battle. Determining whether the protection of a hospital is compromised is an evidence-based exercise, Edgerton said.

Even if a determination is made that a medical establishment has become a military target, Israel must ask itself whether the foreseeable collateral damage would be excessive in relation to the military advantage, she said.

What acts could violate war crimes law?

Human Rights Watch cited as possible war crimes the deliberate targeting of civilians by Hamas militants, indiscriminate rocket attacks and the taking of civilians as hostages, as well as Israeli counter-strikes in Gaza that have killed more than 11,000 Palestinians, including thousands of children, according to figures from Gaza health authorities, deemed reliable by the United Nations.

Hostage-taking, murder and torture are explicitly banned under the Geneva Conventions, while Israel's response could also be subject to a war crimes investigation. Hamas militants stormed from Gaza into southern Israeli communities on Oct. 7 and killed about 1,200 people, mostly civilians, and took about 240 hostages, according to Israeli figures.

In response, Israel laid siege to Gaza, home to 2.3 million people, and launched the most powerful bombing campaign in the 75-year-old history of the Israeli-Palestinian conflict, destroying entire neighbourhoods. Israeli ground forces then swept into Gaza with the stated aim of annihilating Hamas, which runs the enclave.

What do the Geneva coventions say?

Their overarching goal is to protect civilians in wartime.

Under the laws of armed conflict, combatants include members of state armed forces, military and volunteer forces and non-state armed groups.

Directly targeting civilians or civilian objects is forbidden. Intentionally attacking personnel and material involved in humanitarian assistance is a separate war crime as long as those providing the humanitarian aid are civilians.

A siege can be considered a war crime if it targets civilians, rather than a legitimate means to undermine the military capabilities of a force like Hamas, or if found to be disproportionate.

International Criminal Court prosecutor Karim Khan has warned the Israeli army that it will need to show that "any attack that impacts innocent civilians or protected objects" such as hospitals, churches, schools or mosques must be done in accordance with the laws of armed conflict.

Under these laws, civilian objects can become legitimate military targets if they are being used to effectively contribute to military action.

"The burden of proving that the protective status is lost rests with those who fire the gun, the missile or the rocket in question," Khan said.

Israel says Hamas fighters use residential neighbourhoods as cover and civilian buildings to conceal command posts and arms.

If a combatant attacks a legitimate military target, the assault has to be proportional, meaning it must not lead to excessive loss of civilian life or damage to civilian objects.

The Geneva Conventions and subsequent rulings by international tribunals show that proportionality is not a numbers game where the toll of civilian casualties on one side can be compared to the other, rather such casualties should be proportionate to the direct and concrete military advantage expected from that specific attack.

Which institutions can try war crimes?

The first in line to try alleged war crimes are local jurisdictions, in this case courts in Israel and the Palestinian Territories.

The International Criminal Court (ICC) in The Hague is the only international legal organ able to bring charges.

The ICC's founding Rome Statute gives it legal authority to investigate alleged crimes on the territory of its member states or by their nationals, when domestic authorities are "unwilling or unable" to do so.

What does international law say about human shields?

Israel has blamed Hamas for civilian deaths in Gaza, saying that it using Palestinians in Gaza as human shields and hiding arms and command centres centres in hospitals and residential areas.

International humanitarian law forbids the use of human shields and it is considered a grave breach of the Geneva Conventions.

The alleged presence of human shields does not automatically mean that a site cannot be a legitimate military target. However, any attack on such a site must be weighed against the principle of proportionality, looking at the number of civilian casualties compared to the expected military advantage.