ALGIERS, Algeria, July 6 (UPI) -- North African Islamist militants linked to al-Qaida are reportedly building heavily fortified bunkers in the Sahara Desert against airstrikes as Algeria and its neighbors mount a combined offensive against them.
Security authorities in Algeria and Mali, its southern neighbor, have reported construction work in their territories. Fortifications are also being built along the border with Niger, east of Mali.
"The terrorists are building fortified bunkers in mountain areas because they fear they'll come under air attack," said a counter-terrorism official in Timbuktu, Mali.
The militants, member of al-Qaida in the Islamic Maghreb, the Arabic word for North Africa, have also been reported to be laying minefields around their bases to counter ground attacks.
The Algeria-based AQIM compromises an estimated 300 hardcore fighters, most of them members of the now-defunct Salafist Group for Preaching and Combat, which emerged during Algeria's war between Islamists and the military-backed government throughout the 1990s.
That group joined al-Qaida in 2007.
AQIM has sizable forces in the Sahara and operates across the vast ungoverned spaces in Mauritania, Mali, Niger and Senegal.
Its desert forces are led by veteran jihadist Mokhtar Belmokhtar, dubbed "the uncatchable" by French intelligence, which has been hunting him for a decade.
For years, the marauding militants were virtually unassailable in the vast desert region. But now the regional states, led by Algeria, are setting aside traditional rivalries and pooling their resources to go after the Islamists.
Last Thursday, Mali invited Algerian forces to pursue insurgents into its territory after they killed 11 paramilitary policemen in a dawn ambush in the Tamanrasset region near the border with Mali.
It was the deadliest attack AQIM has mounted so deep into the desert, underlining the group's expansion efforts. Mali's response was seen as a mark of regional powers' determination to cooperate against the insurgents.
The attack took place near the recently established operational center for the joint offensive against the Islamists, the Algerian air base at Tamanrasset, hundreds of miles deep in the Sahara.
The regional effort to crush AQIM got under way in January when Algeria, the regional military heavyweight, unveiled a new strategy designed to interdict the jihadist bands and deny them access to water and supplies in the inhospitable Sahara.
The Algerian army deployed 3,000 troops tasked with running the jihadists ragged, reinforcing some 15,000 soldiers operating along the borders with Niger, Mali and Mauritania.
In March, Algeria hosted a conference attended by ministers from Burkina Faso, Chad, Libya, Mail, Mauritania and Niger to determine a region-wide security plan "to root out the scourge of the jihadists."
One of the main obstacles for the new offensive is the lack of transport aircraft to deploy troops rapidly, surveillance aircraft and helicopters. But diplomatic sources say the United States and France may help out and base air units at Tamanrasset.
The counter-terrorism push, particularly in Algeria, seems to be paying off. Several AQIM leader have surrendered in recent months during wide-ranging security sweeps.
One of the most important, Abou el-Abbes, aka Athmane Touati, gave himself up May 25 when Algerian forces surrounded him. Another high-profile figure, Grig-Ahsine Abdelhalim, aka Albdelkader, reputedly close to supreme leader Abdelmalek Droukdel, surrendered the same day.
Counter-terrorism officials in Algiers report AQIM has also been weakened by internal power struggles, which seems to be a perennial problem, between Droukdel and his rivals.
But the officials stress that AQIM remains a dangerous threat across the region.
European intelligence services fear the group may seek to extend its operations across the Mediterranean in the name of Osama bin laden's global jihad.
The United States fears AQIM is moving south into west and central Africa, exploiting the continent's many conflicts and perpetual political unrest, to threaten emerging oil fields that Washington views as an alternative to Middle East oil.
The group's influence has spread considerably over the last few years and U.S. counter-terrorism officials say it's attracting recruits across the region.
In June, AQIM threatened to move into trouble-plagued Nigeria, Africa's second largest oil producer, to join forces with Islamists who have been locked in a religious war with Christians for years.