The attack, which occurred in the town of Reghaia 30 km (20 miles) east of the capital Algiers, was probably carried out by rebel Muslim guerrillas, they said. They had no further details.
Sporadic clashes between rebel forces and security personal normally take place in isolated rural areas.
Muslim rebel began an armed revolt in 1992 after the then military backed authorities, fearing an Iran-style revolution, scrapped a parliamentary election that a Muslim religious political party was set to win.
Up to 200,000 people are estimated to have been killed in the ensuing bloodshed. The violence has sharply subsided in the past few years.

Copyright Reuters, 2006