They stalked in the rain between pine trees along muddy tracks, rifles raised, before dropping into a crouch, many of them too young to remember the 1990s jihadist insurgency that killed 200,000 Algerians.
Two decades after that bloodshed ended, the militant threat in Algeria has mostly been contained. However, al Qaeda and other groups including an Islamic State branch still hold out in some remote areas, mostly in the vast desert border region with Sahel neighbours Mali and Niger.
The operation in Ain Defla was aimed at a small group that the army believed to be hiding in the mountains, about 180 kms (112 miles) west of the capital Algiers.
It had splintered from the Salafist Group for Preaching and Combat, one of Algeria's oldest militant organisations and the forerunner of its al Qaeda franchise, the army said.
Reuters and a local news agency were escorted during the operation by the military.