Who Is Al-Shabaab's Next Target? (VIDEO)

A Somali militant group's claim that it carried out the devastating attack on a popular restaurant in Uganda during the World Cup final triggered widespread fear of a new and frightening threat to innocents in Africa and beyond.

The slaughter on Sunday of at least 76 people who had gathered to watch the game on television in Kampala, Uganda's capital, appears to be the first terrorist strike outside Somalia by Al-Shabaab, a militant Islamic group allied with Al Qaeda.

Al-Shabaab has earned a reputation inside its own country for ruthless determination to seize the strife-torn failed state whose weak, supposedly transitional government is clinging to control of the Somali capital of Mogadishu. Its quest, thanks in part to successful recruiting of Muslims in the West, is often described as a jihad, or holy war. As a correspondent for Current TV's Vanguard, I recently profiled a young American, raised as a Christian in Alabama, who is now a leader in Al-Shabaab and an effective Internet propagandist rallying disenchanted young Muslims in the West to come join the cause.

Kampala is, in once sense, an obvious place for Al-Shabaab to strike, because Uganda is the largest contributor of troops to the African's Union's peacekeeping force that shores its principal target, the existing government in Mogadishu. But the coordinated double bombing also serves as a warning to other African nations--and the West as well--that Al-Shabaab's ambitions are growing. When I was in Mogadishu four years ago, Al-Shabaab was a ragtag band of youths acting as the military arm of the Islamic Court Union, an Islamic coalition that brought momentary calm to the chaos in Somalia. In nearly two decades of disastrous corruption and disruption inside Somalia, hundreds of thousands of Somalis have fled to new communities around the world, including sizable populations in Toronto, Minnesota and elsewhere in North America.

But Al-Shabaab has drawn hundreds of foreign recruits to join its cause its war to establish Islamic rule. They have certainly established their cred among disenchanted exiles, but what has been a recruiting ground could also be a cover for planting cells of homegrown terrorists managed by Al-Shabaab.

Christof Putzel reported from Somalia in 2006 and followed the desperate flight of Somali refugees across the Gulf of Aden in 2008. His most recent documentary, American Jihadi, is now on Current TV. Vanguard airs Wednesdays at 10/9c.