[LibWhacker]

What, some of them only had detonators but no other explosives on them? Dry run using real detonators gone bad?

I think deliberately placed EMP devices can set off detonators. Sounds like the Brits may have been a good step ahead of these scum.

[Semper Paratus]

I think deliberately placed EMP devices can set off detonators.

As John McLaughlin might say "MORRTON you may have stumbled upon the truth".

[Spktyr]

EMP weapons wouldn't set off detonators (in general). They would just fry any solid-state circuitry they contain without doing anything else - i.e., render a cell-phone detonator inert.