Comment by ensignavenger

It is possible that there was an explosive planted, plus some sort of thermal detonator that was triggered electronically, or even that the battery was used as a thermal detonator to detonate an explosive.

While the Note 7 exploded with quite a bit of force, they never caused injuries like these, and the Note 7 likely had much bigger battery than these pagers had.

We won't know for sure until the devices have been examined.