But the operations, including suicide bombings, have gone largely unnoticed because of the Libyan conflict that drove longtime dictator Moammar Gadhafi from power, the third regional autocrat ousted by revolutions of the Arab Spring.
There are growing concerns that vast numbers of weapons looted or missing from Gadhafi's armories in Libya, Algeria's eastern neighbor, may be fueling the jihadist campaign, threatening greater violence in the months ahead.
The primary focus of the jihadists' recent operations is Algeria, which U.S. and European counter-terrorism experts fear could destabilize the former French colony as it struggles to avert a pro-democracy uprising by a disgruntled population galvanized by the Arab Spring.
Throughout the 1990s, Algeria's military regime battled Islamist militants in a civil war that erupted after parliamentary elections the Islamists were set to win were scrapped in 1991.
As many as 200,000 people died in the conflict, with massacres committed by both sides.
By 2002, the war effectively ended with an amnesty for militants declared by President Abdelaziz Bouteflika, although die-hard Islamists fought on.
These days, they have largely morphed into al-Qaida in the Islamic Maghreb, the Arab name for North Africa.
AQIM is active in northern Algeria, with a separate command in the south operating across the ungoverned spaces of the Sahara Desert and the semi-Arid Sahel region stretching from West Africa to Libya.
It is largely involved in kidnapping Westerners for ransom or smuggling, including narcotics, which provide operational funds while the group extends its tentacles in Niger, Mali, Mauritania and even oil-rich Nigeria.
A recent U.S. study by the Combating Terrorism Center at the U.S. Military Academy at West Point, N.Y., zeroed in on the surge of attacks by the northern group, largely directed at Algeria's security forces.
It links the sharp escalation -- at least 23 attacks in July and August - to the Western intervention in Libya to support anti-Gadhafi rebels.
Algerian and other regional leaders have been warning since March that the anarchy in Libya could destabilize Algeria, a leading oil producer and a major supplier of natural gas to Europe.
Algeria has in recent years, especially since 9/11, become a vital, though little publicized, intelligence ally of the Americans in fighting terrorism.
Algeria, as the region's military heavyweight, has escaped the worst of the Arab Spring turmoil that erupted in January, largely by increasing state salaries and boosting public spending funded by oil and gas revenues and lifting the state of emergency declared in 1992.
But discontent is spreading, fueled by the pro-democracy uprisings, even as the military braces for trouble.
On Oct. 1, Prime Minister Ahmed Ouyahia, seen as close to the hard-line generals who dominate Algerian politics, rebuffed moves for greater reconciliation by declaring there would be no amnesty for "terrorists."
There have been persistent reports by European security chiefs that large numbers of Libyan weapons, possibly including 5,000 surface-to-air missiles, have fallen into AQIM hands.
The Combating Terrorism Center warned that if the upswing in Algerian violence continues, growing friction between the generals and Bouteflika, who has promised a new constitution and electoral reforms, could ensue.
"Regardless of what emerges from the in-fighting and tension in Algeria's ruling classes, it seems likely that AQIM's violence will continue to increase in the north," the report concluded.
Underlining the threat, the U.S. Embassy in Algiers recently issued a terrorism alert, saying the Algerian-led AQIM was planning to attack aircraft used by Western oil companies operating in Algeria.
A report by the Center for Strategic and International Studies in Washington in late September warned that AQIM "has been quietly maneuvering itself for a greater strategic role in the Sahel, taking advantage of the chaos in the region to expand its influence and capabilities … beyond its Algerian base."
In Morocco, security authorities say they have smashed three AQIM-linked cells since the April 28 suicide bombing of a Marrakech restaurant that killed 17 people.
Among the suspects is a close relative of Mohammed Moumou, an al-Qaida leader in Iraq killed in 2008. Regional intelligence reports say AQIM wants to develop a Moroccan network for attacks on Europe.
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