Police quickly cordoned off the scene of the car bombing in Bouira
Twelve people have been killed and 42 injured by twin car bombs that hit a barracks and a bus in Bouira, south-east of the Algerian capital.
The government said the blasts went off 15 minutes apart early on Wednesday.
The attacks come one day after a car bomb killed 48 people and injured dozens more at a police college near Boumerdes, east of Algiers.
In recent months Algeria has suffered regular attacks blamed on Islamist insurgents linked to al-Qaeda.
The country has been rebuilding with the help of oil and gas profits after a brutal civil conflict in which Islamist militants led an insurgency against state security forces in the 1990s.
Many recent attacks have happened in the area east and south of Algiers, which borders the mountainous Berber region of Kabylia.
Wednesday's bombs went off at the military headquarters and outside a hotel in Bouira, which is about 100km (62 miles) from Algiers.
The first bomb ripped off the front of the military barracks. It created a crater several metres in diameter.
The second hit a bus transporting Algerian employees of a Canadian company SNC-Lavalin, who were working on a water plant.
The company confirmed that 12 of its Algerian employees had been killed and some 15 others had been injured.
"The bus was left a complete wreck," one eyewitness told Reuters news agency. "Nearby were pools of blood, watches, tattered clothes and a mobile telephone still ringing."
Just a day earlier, a suicide car bomber drove a car packed with explosives into the entrance of a paramilitary police college in Issers, near Boumerdes, about 50km (31 miles) east of Algiers.
That attack hit military police recruits who were waiting outside the building before an exam.
ATTACKS IN ALGERIA 2007-2008
19 August 2008: 48 killed by suicide bombing outside police college in Issers
10 August 2008: Eight killed by suicide bombing outside police station in Zemmouri
8 June 2008: French engineer and driver killed east of Algiers
5 June 2008: Roadside bomb kills six soldiers east of Algiers
January 2008: Suicide bombing kills four policemen in Naciria
December 2007: Twin car bombs kill at least 37 including 10 UN staff in Algiers
8 September 2007: 32 die in bombing in Dellys
6 September 2007: 22 die in bombing in Batna
July 2007: Suicide bomber targets barracks near Bouira, killing nine
April 2007: 33 killed in attacks on government offices and a police station in Algiers
The interior ministry, which said most of those killed were civilians, updated the death toll from the Issers attack on Wednesday to 48.
After the Issers attack, Interior Minister Yazid Zerhouni said militants were trying to "loosen the net closing around them".
Algeria's government has long said Islamist insurgents are desperately seeking to raise their profile as they are isolated by security forces.
There have been no immediate claims of responsibility for this week's attacks.
Previous bombings have been claimed by the North African branch of al-Qaeda, known as al-Qaeda in the Islamic Maghreb.
Those included twin suicide car bombings in Algiers - one against the offices of the UN - that killed at least 37 people in December.
In recent years, Algeria has been slowly recovering from a conflict that began in 1992 when the army intervened to stop hardline Islamists winning the country's first multi-party elections.
Violence has been greatly reduced since the 1990s, but since last year there have been a series of devastating suicide bombings and several attacks against international targets.
Al-Qaeda in the Islamic Maghreb was formed from the remnants of Algeria's insurgency, and was previously known as the Salafist Group for Call and Combat.
Aftermath of Algeria blasts
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