MOPTI, Mali — Deep inside caves, in remote desert bases, in the escarpments and cliff faces of northern Mali, Islamic fighters are burrowing into the earth, erecting a formidable set of defenses to protect what has essentially become Al Qaeda’s new country.
They have used the bulldozers, earth movers, and loaders left behind by fleeing construction crews to dig what residents and local officials describe as an elaborate network of tunnels, trenches, shafts, and ramparts.
In just one case, inside a cave large enough to drive trucks into, they have stored up to 100 drums of gasoline, guaranteeing their fuel supply in the face of a foreign intervention, according to analysts.
Northern Mali is now the biggest territory held by Al Qaeda and its allies. And as the world hesitates, delaying a military intervention, the extremists who seized control of the area last year are preparing for a war they boast will be worse than the decade-old struggle in Afghanistan.
‘‘Al Qaeda never owned Afghanistan,’’ said former United Nations diplomat Robert Fowler, a Canadian kidnapped and held for 130 days by Al Qaeda’s local chapter, whose fighters now control the main cities in the north. ‘‘They do own northern Mali.’’
Al Qaeda’s affiliate in Africa has been a shadowy presence for years in the forests and deserts of Mali, a country hobbled by poverty and a relentless cycle of hunger.
In recent months, the terror syndicate and its allies have taken advantage of political instability within the country to push out of their hiding place and into the towns, taking over an enormous territory which they are using to stock arms, train forces, and prepare for global jihad.
The catalyst for the Islamic fighters was a military coup nine months ago that transformed Mali from a once-stable nation to the failed state it is today.
On March 21, disgruntled soldiers invaded the presidential palace. The fall of the nation’s democratically elected government at the hands of junior officers destroyed the military’s command-and-control structure, creating the vacuum which allowed a mix of rebel groups to move in.
With no clear instructions from their higher-ups, the humiliated soldiers left to defend those towns tore off their uniforms, piled into trucks, and beat a retreat as far as Mopti, roughly in the center of Mali.
They abandoned everything north of this town to the rebels, handing them an area that extends over more than 240,000 square miles.It is a territory larger than Texas or France.
Turbaned fighters now control all the major towns in the north, carrying out amputations in public squares like the Taliban did. Just as in Afghanistan, they are flogging women for not covering up. Since taking control of Timbuktu, they have destroyed seven of the 16 mausoleums listed as world heritage sites.
The area under their rule is mostly desert and sparsely populated, but analysts say that due to its size and the hostile nature of the terrain, rooting out the extremists here could prove even more difficult than it did in Afghanistan.
Mali’s former president has acknowledged, according to diplomatic cables, that the country cannot patrol a frontier twice the length of the border between the United States and Mexico.
Al Qaeda in the Islamic Maghreb, known as AQIM, operates not just in Mali, but in a corridor along much of the northern Sahel.
This 4,300-mile-long ribbon of land runs across the widest part of Africa, and includes sections of Mauritania, Niger, Algeria, Libya, Burkina Faso, and Chad.
‘‘One could come up with a conceivable containment strategy for the Swat Valley,’’ said Africa expert Peter Pham, an adviser to the US military’s African command center, referring to the region of Pakistan where the Pakistan Taliban have been based. ‘‘There’s no containment strategy for the Sahel, which runs from the Atlantic Ocean to the Red Sea.’’