"During anti-terrorist operations, an army unit killed three terrorists today after an attempted ambush in the Tagrara area" 150 kilometres from Algiers, it said in a statement.
The ministry said two Kalashnikov assault rifles and a large quantity of ammunition and explosives was also recovered.
Violence involving armed Islamists in Algeria has fallen considerably since the civil war of the 1990s, but groups linked to Al-Qaeda in the Islamic Maghreb still carry out some attacks, mostly on security forces.
The Algerian army says more than 100 armed Islamists were killed in 2014.