No group has claimed responsibility for the recent spate of killings, including the two remote-controlled car bombs that struck the city of Bouira on Wednesday. But all six occurred in the area east of the capital where militants from an Algerian offshoot of al Qaeda are suspected to operate.
Violence in this gas- and oil-rich U.S. ally has surged since the homegrown extremist group GSPC, which led a deadly insurgency in the 1990s, joined Osama bin Laden's network in 2006 and took the name Al Qaeda in Islamic North Africa.
The death toll surged to more than 70 this month alone, and the relentless bombings led many newspapers to question whether authorities have grown too lenient, or too weak, to fight Islamist extremists.
Terrorism expert Jean-Louis Bruguiere says the group is receiving military reinforcements from al Qaeda in Iraq and using Algeria as a "platform" from which to spread instability throughout North Africa and possibly beyond.
"The security situation is deteriorating, and it's worrisome for Europe," said Bruguiere, formerly France's top counterterrorism judge and now the European Union coordinator of a terrorism finance tracking program jointly run with the United States.
Interior Minister Yazid Zehrouni, however, insisted the string of attacks suggest that extremist groups are "riddled with internal problems and are mainly aiming to raise internal troop morale."
Wednesday's two car bombs were triggered by remote control. The first hit a regional military command and injured four soldiers in Bouira, some 55 miles (90 kilometers) southeast of the capital, the state-run APS news agency reported.
A minute later, at least 12 people died and 27 were wounded when a second bomb exploded next to a nearby downtown hotel. Most of the victims were traveling in a bus that passed in front of the hotel, APS said.
All those who died and about 15 of the wounded were Algerian employees of SNC Lavalin, a Montreal-based engineering and construction firm, the company said in a statement. They were on the bus headed to work on a water treatment plant and distribution project.The number of injured was from the APs report.
Most victims were civilians traveling in a bus that passed in front of the hotel. Local hospital officials said they were workers from a construction company building a dam nearby.
The military barracks were most damaged. "Parts of the walls have fallen off, the fence is destroyed, cars are buried under the rubble," Abdellah Debbache, the Bouira correspondent of Algeria's Liberte newspaper, told The Associated Press by telephone.
A day earlier, a suicide bombing some 28 miles (45 kilometers) away in Les Issers killed 43 people in Algeria's biggest attack since the 1990s. The bomber targeted young students lining up to apply at a police academy, and at least 45 were injured.
"Terrorism: is the State powerless?" asked a large headline on the independent El Watan newspaper's cover, which carried a single, large photograph of the bloodbath.
Several other Algerian newspapers also questioned whether a "national reconciliation" policy voted in 2005 to grant widespread amnesty to Islamists was giving radical groups too much space to regroup and find new support.
Algeria's insurgency broke out in 1992 when the secular-leaning army canceled legislative elections that an Islamist party was expected to win, and it claimed up to 200,000 lives. The insurgency largely died out before insurgents got a new boost by joining forces with al Qaeda.
Today, extremists focus their efforts against security forces and foreigners.
On Sunday, extremists ambushed and then beheaded 12 people, including 11 security officials in Skikda in eastern Algeria. A soldier and the head of the nearby military region of Jijel were killed on Aug. 14; a suicide bombing four days earlier killed eight people at a police station in Zemmouri next to Algiers. A suicide bombing wounded 25 on Aug. 3.
Several newspapers said the GSPC's original founder issued a condemnation of Tuesday's attacks. "Quit all subversive action," Hassan Hattab was quoted as saying, calling the armed insurgency "a dead end." Hattab, who has been dismissed by the more militant members of the GSPC, lives in an undisclosed location. The authenticity of his statement could not be independently verified.