A message purported to be from al-Qaeda's North African wing said it carried out bombings that killed about 60 people in Algeria this week.
The statement, which was sent on an audio tape to the Arab satellite network al-Jazeera, could not be independently verified.
It said the attacks had been carried out in revenge for an ambush in which Islamist militants had died.
The attacks took place on Tuesday and Wednesday east of the capital, Algiers.
The first was a suicide car bombing that targeted civilian candidates waiting to take a recruitment exam at a police college in Issers, 50km (31 miles) east of Algiers, killing 48 people.
A day later, two more car bombings struck in quick succession in Bouira , about 100km (62 miles) south-east of Algiers.
The second explosion in Bouira killed 12 Algerian employees of the Canadian engineering and construction firm SNC-Lavalin.
Al-Qaeda's North African wing, known as al-Qaeda in the Islamic Maghreb, has claimed a series of suicide bombings and attacks against international targets in Algeria over the last 18 months.
The attacks have come as Algeria is rebuilding after a brutal civil conflict involving Islamist insurgents and state security forces that began in 1992.
The last significant group from the insurgency, the Salafist Group for Call and Combat, changed its name to al-Qaeda in the Islamic Maghreb early last year.