"At least eight people were killed and 2,750 others including Hezbollah fighters, medics and Iran's envoy to Beirut were wounded on Tuesday when the pagers they use to communicate exploded across Lebanon, security sources and the Lebanese health minister said...
Lebanese internal security forces said a number of wireless communication devices were detonated across Lebanon, especially in Beirut's southern suburbs, a Hezbollah stronghold. The pagers that detonated were the latest model brought in by Hezbollah in recent months, three security sources said."
I saw footage of one explosion and it was pretty powerful. I've seen lithium batteries explode before and they seem way less violent. Guess they're chunky (and cheap?) batteries