A former British army munitions officer told the BBC the devices could have been packed with as little as 10 to 20 grams of high explosive hidden inside fake electrical parts.
The former officer, who asked not to be named, said such a package could have been armed by a signal, with the next person to use the device triggering an explosion.
Bogdan Botezatu, head of threat research at cyber security company Bitdefender, said on X: “Hacked pagers and phones don’t randomly explode unless they are already attached to a nice ball of Semtex.
“Worst case, (lithium ion) batteries first catch on fire, then they go kaboom.”
The attack threatens to escalate simmering tensions across the Lebanese border, with Israel and Hezbollah engaging in repeated strikes since Oct 7 last year.
A statement by the Iran-backed group said Israel would get “fair punishment”.
Hezbollah had been known to use pagers as a low-tech solution to avoid Israeli signals intelligence. Hassan Nasrallah, the Hezbollah leader, had previously urged fighters not to carry mobile phones, warning they were “deadly agents”.
He has previously said that smartphones were “surveillance devices in your pockets. If you are looking for the Israeli agent, look at the phone in your hands”.
The Wall Street journal reported that medical staff across Lebanon were discarding their own pagers, which are routinely used in hospitals around the world to send rapid text messages to colleagues.
Lebanon’s state-run National News Agency blamed the attack on the “handheld pagers system [which] was detonated using advanced technology”.
Hezbollah officials, meanwhile, said the attack represented the group’s “biggest security breach” since Oct 7 last year.