Two vehicle bombs exploded outside two police stations in attacks in two towns east of the Algerian capital during Sunday night.
The near-simultaneous blasts took place in Reghaia, 30km (20 miles) east of Algiers, and neighbouring Dergana.
According to witnesses, at least one person was killed in the attacks and about 14 were injured.
The blasts were believed to have been carried out by Islamist rebels in the most sophisticated attacks in years.
Sporadic clashes between militants and security officers normally take place in rural areas.
In Reghaia, a grenade was thrown into the police station after a truck laden with explosives had been parked outside, AFP news agency reports.
Police were reported to have fired on men who had been in the truck as they fled from the scene in a waiting car.
The blast, detonated remotely, hurled vehicle parts across the street, tore a hole in the two-storey building and burnt out 18 parked cars.
Police cordoned off the area around the blast scene in Dergana so details were not immediately available.
Militant Algerian groups have killed some 150,000 people since 1992, when elections in which an Islamic party was poised to win were cancelled.