The Djebahia region, some 45 miles east of the capital, is a stronghold of al Qaeda in the Islamic Maghreb (AQIM) which earlier this month killed 37 foreigners at a gas plant in the south, and is where its leader Abdelmalek Droukdel is believed to be based, the source said.
Militant attacks are rare in the country's north due to a heavy security presence that pushed most AQIM activities south.
"In comparison to the In Amenas incident, this is a very minor event," the source said, referring to the gas plant attack.
Droukdel is believed to be somewhere in a triangle of three northern cities: Boumerdes, Bouira and Tizi Ouzou, about 1000 miles (1600km) from In Amenas, and has limited contact with other senior members of the group, the source said.
"The links are almost non-existent, and evidence of that is there are no Libyan weapons with AQIM's militants in the north," a security source who asked not to be named said.
The In Amenas attackers used arms smuggled across the desert border with Libya.