Looks like a hardware supply chain attack: https://goachronicle.com/hezbollah-members-pagers-exploded-i...
>>GoaChronicle through its intelligence network has learned that Israeli intelligence successfully intercepted a shipment of pager batteries that had been ordered from B&H Photo. The order was placed from Lebanon. Acting on a confirmed tip, the intelligence agency seized the shipment and covertly modified the batteries. Small, undetectable explosives known as Kiska 3 were inserted into the battery casings and connected to the battery wires via a discreet chip. The pager model was Rugged Pager AR924 IP67. The operation code word was ‘Below the Belt’.