The huge wave of pagers/beepers exploding in Lebanon and Syria yesterday, very probably by Israel, can be called a major war crime or an act of mass-terrorism, but it certainly seems to me that it can not be considered as compliant with the laws of war.
Rule 15. In the conduct of military operations, constant care must be taken to spare the civilian population, civilians and civilian objects. All feasible precautions must be taken to avoid, and in any event to minimize, incidental loss of civilian life, injury to civilians and damage to civilian objects. https://ihl-databases.icrc.org/en/customary-ihl/v1/rule15
Rule 19. Each party to the conflict must do everything feasible to cancel or suspend an attack if it becomes apparent that [...] the attack may be expected to cause incidental loss of civilian life, injury to civilians [...] which would be excessive in relation to the concrete and direct military advantage anticipated https://ihl-databases.icrc.org/en/customary-ihl/v1/rule19
Note that those "rules" are summaries of all customary international humanitarian law (non-voluntary global laws of war) by ICRC, responsible for maintenance of e.g. Geneva Conventions, while the underlying conventions and practices are cited on each page for further reference.
One of the people killed by the very probably Israel's wave of pagers/beepers terrorism in Lebanon yesterday was Fatima Jaafar Abdullah (depicted), 10 years old, reports Expressen, one of the two major evening papers of Sweden citing "several Arab media" and further stating "that a child has died in the attack has also been confirmed by Firas Al-Aiad, Lebanon's Minister of Health, and by the Shia militia Hezbollah themselves. It is still unclear if there are more children among the deceased."
"Blasts by pager devices injure 14 people in Syria" https://npasyria.com/en/116941/ In the same wave of terror-attacks very probably committed by Israel more widely hitting people in Lebanon resulting in now at least 2800 people injured and 9 dead.
There are much, much worse videos and photographs of the results of the very probably Israeli beepers/pagers-terrorism in Lebanon. I will not share those forward. Don't look for them. You do not need to see children like that. No, you really don't. I will not go into further detail.
Also... Israel acceded to the 1980 "Convention on Certain Conventional Weapons", all protocols, among which is the "Protocol on Prohibitions or Restrictions on the Use of Mines, Booby-Traps and Other Devices", by which e.g. "It is prohibited to use booby-traps or other devices in the form of apparently harmless portable objects which are specifically designed and constructed to contain explosive material.", etc, etc http://treaties.un.org/doc/Treaties/1996/05/19960503%2001-38%20AM/Ch_XXVI_02_bp.pdf Seems pretty clear to me.