A municipal guard and two soldiers were killed in a gun fire exchange with fighters on Saturday night in the mountains on the outskirts of Gouraya, 100km west of the capital Algiers amid a military sweep on their hideouts.
A civilian was killed on Saturday near Thenia, 50km east of the capital, security sources said.
Authorities were not immediately available for comment.
Separately, official media said three fighters of the Salafist Group for Preaching and Combat (GSPC) died in a vast military operation in Relizane, west Algeria.
Algeria's military has been fighting anti-government fighters since they took up arms to overthrow authorities and set up an Islamic state.
The conflict was sparked by the annulment of elections an Islamic party was poised to win in 1992.
Violence has sharply fallen in recent years, although the GPSC remains the North African country's largest armed anti-government movement.