Explainer: Five Things To Know About Al-Shabab

Kenyan police take cover outside the Westgate shopping center in Nairobi where gunmen from Somalia's Al-Qaeda-linked Al-Shabab movement went on a shooting spree on September 21.

The Islamic fundamentalist Al-Shabab group in Somalia is little known outside East Africa. But its attack on a Nairobi mall reveals it to be one of the strongest and most capable Al-Qaeda affiliates.

What Is Al-Shabab?

Al-Shabab, which means "The Youth" in Arabic, emerged in war-torn Somalia in 2006.

It is a radical Sunni group, which, at its peak of power, ran much of southern Somalia but has now been pushed back into rural areas by African Union forces, predominantly Kenyan, which are trying to stabilize Somalia and support its weak government.

The group enforces strict Shari'a law in the areas it controls, including stoning to death women accused of adultery and amputating the hands of thieves.

Al-Shabab has twice struck back at neighboring countries supplying forces to stabilize Somalia. It coordinated a bombing attack against Uganda that killed 76 people in Kampala in 2010. Now it is claiming responsibility for this week’s attack on a mall in the Kenyan capital, Nairobi, which has killed at least 69 people.

What are Al-Shabab’s connections to Al-Qaeda?

Al-Shabab's current leader, Mukhtar Abu Zubair, pledged allegiance to the global terrorist movement in February 2012. But exactly who controls how much of Al-Shabab and for how long is unclear.

The current attack on Nairobi might suggest that Abu Zubair, who often speaks of the need for global jihad, is now taking the Somali group in the same direction as Al-Qaeda. He has waged an internal power struggle in which several rivals who see Al-Shabab as purely Somalia-focused were killed or have fled.

But, according to Peter Lehr, a regional expert at the Center for the Study of Terrorism and Political Violence in Scotland, just how much Al-Shabab is truly linked to Al-Qaeda remains to be seen.

"One has to remember that Al-Shabab is not a really unitary, strictly hierarchical organization," he says. "It is basically kind of an alliance of important clerics with their own troops, and it ranges from radical extremists to very moderate ones, so if some spokesperson says, 'We are part of Al-Qaeda,' some others might have a different point of view than that."

Anna Rader, a research associate focusing on the Horn of Africa at the London-based Royal United Services Institute, also believes the strength of Al-Shabab's commitment to Al-Qaeda's global jihad remains far from clear.

"I think we shouldn't underestimate the fact that Al-Shabab has been sponsored by some of the clans in southern Somalia and that there is some sort of accountability as to how much Al-Shabab is providing a framework of security and justice, which has kind of enabled life of some kind to go on in these very desperate areas of southern Somalia," she says. "And if it starts pouring its resources into international jihad, which is not what tribal leaders in the south want, you might see a lot of friction there."

For these reasons, the Nairobi attack is better regarded as an attack designed to weaken Kenya's commitment to the African Union force in Somalia than as an effort to advance global jihad.

How strong is Al-Shabab?

No one knows exactly how many fighters Al-Shabab has, but many estimate they number around 5,000, including several hundred foreign fighters. The force, which is well armed, is believed to have been weakened considerably since having to retreat from Mogadishu in 2011 and from its economic base in the port of Kismayo in 2012.

How strong an appeal Al-Shabab still has in Somalia is also a question. The group was initially welcomed by many for its promise to deliver security, but its brutal enforcement of Shari'a law and its levying of heavy taxes in areas it controls have increasingly alienated the population.

The fact that Al-Shabab adheres to the Saudi-inspired Wahhabi version of Islam, while most Somalis are Sufis, also creates tensions, particularly as the group destroys Sufi shrines.

Some analysts see the attack in Nairobi as an attempt to show the world that Al-Shabab is still a force despite recent setbacks. Its ability to strike across the border at Kenya, while it also continues regular suicide bombings in Mogadishu, could impress potential recruits that it remains able to strike its enemies both at home and abroad.

Does Al-Shabab pose a danger outside of East Africa?

This is a question of great current concern to Western countries, like the United States and United Kingdom, which have large Somali communities.

U.S. Representative Peter King, a member of the House Homeland Security Committee, said on September 22 that Al-Shabab had recruited up to 50 people from Somali communities in the United States. He said there was concern some may return from Somalia and "use their abilities in the United States."

Peter Lehr says that Al-Shabab may indeed be interested in fund-raising in Somali diasporas and even recruiting fighters there. But he suggests that the movement's main focus is the war in Somalia, not opening distant new fronts.

"Whether they are really interested in carrying the fight to the West, that is, the United Kingdom or the United States, is anybody's guess," he says. "The question is: can Al-Shabab support that? Can they finance that? Do they have enough operators to make do without, because the core for them is fighting and winning the guerrilla war in Somalia itself. Everything else is a sideshow.”

What does Al-Shabab’s Nairobi attack say about the evolving tactics of terror groups?

To strike Kenya, Al-Shabab launched a military-style assault against a soft civilian target. The attack shares much in common with the terrorist attack in Mumbai in November 2008, which set a precedent for small teams of well-trained fighters going on a shooting spree against civilians.

Some analysts believe the fact that the Nairobi attack so closely followed the Mumbai model is no accident. Bruce Reidel, a U.S. expert on terrorism and formerly of the CIA, says that "the biggest surprise is that we have not seen more people try to emulate that tactic sooner."

The Mumbai attack was planned by a former Pakistani military officer who was a senior manager for Al-Qaeda until he was killed in 2011 by a U.S. drone strike. Al-Shabab is believed to have regular communication with Al-Qaeda, making it possible that the Nairobi tactics are an example of information exchanges between the two groups rather than simply coincidence.