The killing of some 20 Algerian paramilitary policemen in a desert ambush Wednesday by Islamist extremists linked to al-Qaida was a show of force by the jihadists who appear determined to expand their operations across the region and open a new terror front.

The ambush was the work of al-Qaida in the Maghreb, the Arabic name for North Africa. It was formerly known as the Salafist Group for Preaching and Combat, one of the most vicious Islamist groups to emerge from Algeria's civil war throughout the 1990s. It swore allegiance to Osama bin Laden's global network in September 2006.

The group has a hard core of an estimated 500 to 800 fighters, a fraction of the tens of thousands active during the war between Islamists and the military-backed regime in Algiers, in which an estimated 200,000 people perished.

But its alliance with Osama bin Laden has meant it has acquired seasoned fighters from other al-Qaida affiliates, many of them veterans of the insurgencies in Iraq, Afghanistan and more recently Pakistan.

Wednesday's attack serves as an illustration of the Algerian group's growing expertise in guerrilla warfare that are straight out of the jihadist manual developed in Iraq, with considerable influence from Hezbollah's 27-year-old war in Lebanon against Israel.

Arab and Western intelligence sources are convinced that al-Qaida in the Maghreb is seeking an operational alliance with other jihadist groups in Morocco, Tunisia and Libya.

At the same time it is expanding its reach deep into the largely ungoverned areas of the Sahara region in Mauritania, Mali and Niger. It envisions this as the western end of an Islamic caliphate stretching across the Middle East and North Africa to replicate Islam's glory days in 8th and 9th centuries.

Europe too is a target. Six cells linked to the Algerian network have been rolled up in France in recent years, successors of cells set up there in the 1990s. Other cells have been uncovered in Italy and Spain.

Al-Qaida in the Maghreb operates largely in eastern Algeria, where Wednesday's murderous ambush took place. But it controls a vast stretch of territory in the southern Sahara along the borders with Mauritania and Mali. This zone produces much of its funding through drug-smuggling and kidnappings.

In another ominous milestone, the group declared in early June that it had executed a British hostage, Edwin Dyer, 60, who was kidnapped Jan. 22 with three other Europeans after attending the Anderamboukane festival of nomadic culture in Mali. They were apparently abducted by rebel Tuareg tribesmen who handed them over to al-Qaida in the Maghreb.

The jihadists had demanded the British release Abu Qatada, a Jordanian cleric described as bin Laden's right-hand man in Europe. The British have held him since 2005 pending extradition to Jordan, where he has been sentenced to life imprisonment. London refused to let him go.

The dominant al-Qaida figure in the region is Mokhtar Belmokhtar, a veteran jihadist who has eluded capture for almost two decades. The Washington-based Jamestown Foundation, which monitors global terrorism, recently identified him as "a gravitational force in the North African arena and at times a key node in al-Qaida's international network."

He is at odds with the current leader of al-Qaida in the Maghreb, Abdelmalek Droukdel, who took that position in June 2004. Belmokhtar felt he should have got the promotion.

He played a key role in forging the alliance with the global al-Qaida network and has been behind the kidnapping of several groups of Westerners in his Sahara domain since 2003. These reportedly brought him millions of dollars in ransom payments as well as the release of key Algerian jihadists held by the regional powers.

Despite his feud with Droukdel, he remains the group's primary arms supplier and financier and will play a key role in its expansion plans. Expect more kidnappings.