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The process proved more difficult than anticipated, and by nightfall, only three of the bombs had been dealt with. At first, sappers tried to detonate the bombs electronically, but that failed. Sniffer dogs and robots, therefore, had to be sent in to determine the bombs' exact location so that IDF snipers could set them off by firing at them. Even so, it took 20 minutes of steady firing to get three of the bombs to explode, and the other five never went off at all - apparently because the sniper fire had severed the cables connecting them to their fellows. Additional fire at the remaining bombs failed to set them off.
<snip>
The army is at a loss for explanations as to why the northern border is suddenly heating up just as the prisoner swap with Hezbollah seems to be gaining steam. It is particularly worrisome, IDF sources said, that Hezbollah seems to be expanding its anti-Israel operations beyond the Har Dov region, to which it had until now largely confined them. The bombs were not in the Har Dov area.
http://www.haaretz.com/hasen/spages/358076.html