The French have been advancing through the western entrance of the mountain range while the Chadians entered the eastern point
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Both the French and the Chadians engaged in the fiercest fighting last month, inflicting heavy casualties on the insurgents, including one of the most violent al-Qaeda field commanders, Abou Zeid.
French forces have been trying to uproot al-Qaeda from what they say was its "sanctuary"
The Chadians then formed a buffer force leaving time for the French to search valley after valley, hill after hill
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"We first used heavy artillery, jets and helicopters to downsize the enemy from a reasonable distance," Col Benoit Desmeulles, Commanding Officer at the Foreign Legion, said.
"We then started to clear all the caves in the valleys, which was down to man-to-man fighting.
"We clear caves with grenades before entering them
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Caches are being found every day, full of weapons, ammunition and food supplies.
After climbing yet another rocky crest, the unit we were following found explosive belts ready for use, mortars and 100kg of nitrate for the manufacture of improvised explosive devices (IEDs).
De-mining engineers immediately destroyed it all in a controlled explosion.