[txhurl]

"...linked to a triggering mechanism that can be activated by a clock or, in the newer models, a call from a cell phone."

What I'd do is over the course of a week, have middle-east/Iraq cellular companies call all known numbers in service, actuating the ones commissioned to bombs but still in the bomb-making facilities.

[Quix]

Love your creative thinking. Perhaps do so every 30 min during rush hours beginning 30 min before rush hours?