Mossad agents reportedly placed Pentaerythritol tetranitrate (PETN), a highly explosive material, inside the batteries of the pagers, sources told Sky News Arabia, according to a translation from the Times of Israel. The devices were then detonated by an external signal that caused the batteries inside to overheat, the sources added.

Israel’s Mossad spy agency planted explosives inside thousands of pagers imported by Lebanese group Hezbollah months before they detonated, a senior Lebanese security source and another source told Reuters.

A wave of blasts emanating from Hezbollah pagers in Lebanon took place as people shopped for groceries, sat in cafes and drove in cars.