LONDON — The series of explosions that rocked Lebanon this week, killing dozens and wounding thousands, has prompted heated debate among legal experts on international humanitarian law.

Many, but not all, of the pagers and walkie-talkies that unexpectedly blew up over two days across Lebanon and in some neighboring countries were in the possession of Hezbollah fighters, functionaries or allies.

The group is designated as a terrorist organization by several nations, including the United States, but many of its members and supporters operate in civilian areas across Lebanon — and some of the explosions left innocent bystanders, including children, injured or dead.

Israel has not officially acknowledged playing a role in the explosions. But a U.S. official, who was not authorized to speak publicly, told NPR that Israel notified Washington that it was responsible for Tuesday’s attacks.

Several international treaties and protocols to which Israel is a signatory could render these actions by a state such as Israel illegal under international humanitarian law, scholars say.

One particular focus is Article 7(2) of the Amended Protocol II of the Convention on Certain Conventional Weapons, which was added to an international law focused on the use of conventional weapons in 1996. Both Israel and Lebanon have agreed to it.

It prohibits the use of booby traps, which Lama Fakih, Middle East and North Africa director at Human Rights Watch, defines as “objects that civilians are likely to be attracted to or are associated with normal civilian daily use.”

In a statement, Fakih said the use of “an explosive device whose exact location could not be reliably known would be unlawfully indiscriminate, using a means of attack that could not be directed at a specific military target and as a result would strike military targets and civilians without distinction.” Human Rights Watch has called for an immediate and impartial investigation into the incidents.

“Israel is a party to that Protocol,” wrote Richard Moyes, a director at Article 36, an advocacy group that focuses on international law in the context of civilian casualties in conflict zones. In a message to NPR about the rule, commonly known as Article 7(2), he wrote of the attacks: “I think there are lots of other legal problems here under the general rules of war — but it feels like it is a direct breach of this rule.”

Brian Finucane, a former legal adviser on the use of military force at the U.S. State Department, told NPR’s Morning Edition on Friday that information obtained since the explosions “implicate[s] Israel in these attacks, and also suggests that these attacks violate this prohibition on the use of booby traps or other devices in this fashion.”

Finucane pointed out in a post on the website Just Security that the U.S. Defense Department also references that same article from those amended 1996 protocols in its own “Law of War Manual,” with an oft-cited example of communications headsets that Italian military units booby-trapped with explosives after retreating during World War II.

Finucane, now a senior adviser at the International Crisis Group, told NPR that broader internationally recognized and ratified laws of war contained requirements that parties to a conflict take “feasible precautions to minimize harm to civilians” and “take into consideration proportionality when launching attacks.” 

But he said at this stage it was complicated to reach a conclusion about proportionality and targeting just yet, without more facts being known about the attacks. “Were they limited to fighters in Hezbollah? Were they distributed more widely within the organization? Were they distributed to its civilian population?” he said, repeating questions for which there are no current answers. “It’s also very difficult to know what Israel officials who launched the attack knew about the locations of people carrying these pagers, if anything.” 

A group of United Nations human rights experts called the simultaneous explosions “terrifying” violations of international law. “To the extent that international humanitarian law applies, at the time of the attacks there was no way of knowing who possessed each device and who was nearby,” the experts said. “Simultaneous attacks by thousands of devices would inevitably violate humanitarian law, by failing to verify each target, and distinguish between protected civilians and those who could potentially be attacked for taking a direct part in hostilities.”

And Jessica Peake, an international law professor at the University of California, Los Angeles School of Law, told The Intercept that “detonating pagers in people’s pockets without any knowledge of where those are, in that moment, is a pretty evident indiscriminate attack,” and that the attacks were — in her view — “quite blatant, both violations of both proportionality and indiscriminate attacks.”

However, other legal scholars and academics argue the attacks were entirely defensible under international law.

“The operation passes all fundamental laws of war necessity, proportionality, and distinction,” John Spencer, chair of Urban Warfare Studies at the Modern War Institute at West Point, told Newsweek. “It was a very precise sabotage of an enemy piece of equipment used for military purposes.”

William H. Boothby, a retired air commodore in the United Kingdom’s Royal Air Force, wrote for the Lieber Institute at West Point that it was “probably reasonable for those planning and conducting the operation to assume that pagers issued for military purposes would be in the possession of their military users at the time of detonation.”

But, as former deputy director of Royal Air Force Legal Services, Boothby said concerns about the manner in which the attacks were targeted would center on “whether adequate consideration was given to the incidental injury and damage to be expected from these explosions,” since those responsible for detonating the devices could not have been certain of the circumstances in which so many different explosions would occur.

The attacks have drawn political condemnation by some U.S. lawmakers for their perceived violation of international law, including Democratic Rep. Alexandria Ocasio-Cortez of New York. She posted on X that the explosions, which she attributed to Israel, had occurred in across public spaces, killing and injuring innocent civilians.

“This attack clearly and unequivocally violates international humanitarian law and undermines U.S. efforts to prevent a wider conflict,” she wrote.