Africa's Sahel belt is a 600-mile-wide semiarid zone stretching from Senegal in the west to Somalia in the east. The vast, seemingly ungovernable terrain has become a sanctuary for Islamist militants.
After the Arab Spring, and then at the end of Muammar Qaddafi's dictatorship, many hoped for an end to terror in the Sahel.
Instead, weapons spilling out of Libya and ongoing military efforts to drive Al Qaeda-linked groups from places like Mali and Nigeria have hardened Islamist fighters here. This in turn has increased the risk of violence across the region.
French Foreign Minister Laurent Fabius has called the area "Sahelistan," likening it to remote areas in Afghanistan where US troops struggled for years to pin down the Taliban. The French Army in January intervened whole-scale in Mali to drive Islamist radicals out.
The Sept. 21 bloody siege on Nairobi's Westgate mall was carried out by a Somali-based group called Al Shabab that is in decline and had been little noticed. But by tying up the Kenyan security forces for four days in the nation's capitol and leaving 61 or more dead, including diplomats and a prominent African-Ghanian poet, Al Shabab, which means, "the youth," put themselves on the Sahel terror map.
Likewise, the Nigerian radical Islamist Boko Haram group, which acts like a cult, on Sept. 29 carried out another slaughter of the innocent by reportedly killing 50 students sleeping at a state agricultural college. Boko Haram, which translates as "Western education is sinful," has been on a killing spree this summer that has included dozens of schoolchildren and dozens of moderate Muslims attacked while praying in their mosque.
The Sahel groups are reportedly small but their influence is felt where they are based, in Guinea, Nigeria, Burkina Faso, Senegal, Niger, Mauritania, Somalia, and Sudan. The worry in the West is that extremists will use the Sahel to launch terror attacks overseas.
In May the United Nations Security Council warned that insurgencies here, "if left unchecked, could transform the continent into a breeding ground for extremists and a launch pad for larger-scale terrorist attacks around the world."
Jihadi impulses in the Sahel are progressively moving into new areas, as Islamists of different stripes shift and change. The groups, some of them ad hoc, are forging relations with their more established Al Qaeda counterparts.
In August, for example, two Sahel-based terror groups responsible for high-profile attacks in Niger announced they were joining forces. In West Africa, the prospect is a worrying one. Both groups are Al Qaeda spinoffs. They both fought the French in Mali last winter.
Now, in their new incarnation as an entity called Al-Mourabitoun, they promise to attack French interests and infrastructure and those of France's allies. In May, they hit a uranium mine project owned by French nuclear giant Areva that was supposed to go on line in 2012. The ensuing delays have cost millions.
"The security context is not very conducive to growth," said an International Monetary Fund official in Niger.
Ground conditions in and along the Sahel are troubling: There's near anarchy in places. The number of angry youths is rising. So is radical rhetoric. Poverty and corruption, and a lack of jobs and education, are the backdrop across an unstable region.
For those monitoring jihad in the Sahel, the West African state of Mali is considered the linchpin in the fight. An uprising in Mali last year was hijacked by Al Qaeda-linked jihadists who took sizable chunks of territory in the north. They implemented sharia, or Islamic law, and threatened to take down the government.
Then, in January a French-led military intervention in Mali drove the Islamists mostly out of the north. But many insurgents escaped, and in the process established a broader geographic footprint. French President François Hollande said from Mali's capital Sept. 19 that if France had not intervened, "today the terrorists would be here in Bamako."
Yet "it is a mistake to see Mali as over and done with," says John Campbell, the former US ambassador to Nigeria.
Unless the newly elected Malian government can restore order in the north of a country almost twice the size of France, Islamists could revive their rebellion. They are already trying to export their methods and ideology to neighboring countries that have small military budgets and that are vulnerable to extremism.
"While the initial military operations led by the French and Chadian forces inflicted heavy losses on the Islamists," says Roddy Barclay, a West Africa analyst at Control Risks in London, "they have been able to exploit the vast ungoverned spaces, porous borders, and challenging terrain of the Sahara to avoid total defeat."
For example, the new Al-Mourabitoun consolidates two small but powerful Islamic groups that have begun to exploit the Sahel.
One group was known as the "Battalion of those who sign with blood," and run by Mokhtar Belmokhtar, called "Mr. Marlboro" for his local cigarette-smuggling empire.
Mr. Belmokhtar is an Algerian and was the lead planner of a January attack on a gas plant in Algeria that left 37 hostages dead, including three Americans. He faces terrorism charges in the United States, and $5 million is offered for information leading to his arrest.
The other group was an Al Qaeda variant called Movement for Unity and Jihad in West Africa, led by a Mauritanian, Hamada Ould Mohamed Kheroo. Whether Al-Mourabitoun has a leader isn't clear. But the group's stated focus remains French interests and those of France's allies, which in the past have been rhetorical and operational targets of both Al Qaeda in the Islamic Maghreb (AQIM) and Belmokhtar.
In May, that focus turned from Mali to Niger, next door. Niger supported the French intervention in Mali, and on May 23 came payback. The groups hit a uranium mine run by Somair, a subsidiary of Areva. They also attacked a military barracks, killing 35. The attacks were the first instance of militant suicide bombings in Niger.
So Islamist extremism arrived in a country of 17 million, with porous borders, spread over a sandy land whose moonscape terrain provides excellent hiding places.
The problem comes as Niger President Mahamadou Issoufou wants to secure uranium production, which accounts for more than 70 percent of his nation's export earnings. He wants to prevent an impoverished population, mostly reliant on subsistence farming, from being drawn into Islamist extremism.
Given the importance of uranium to Niger's economy, infrastructure surrounding the industry is a high-profile target. Security has been bolstered at a mine in Akokan that is a joint venture between Areva and Niger.
Djibril Arbarchi is a legislator from the capital, Niamey, who sits under a tree to avoid the fierce desert sun.
"People are tormented. They are living hand to mouth," Mr. Arbarchi says. He stands watching a 14-year-old boy pulling a donkey and cart through Niamey's sandy streets. The boy says he forages in the outskirts of the city for firewood, which he sells for less than a dollar.
"We all know that where there is poverty and unemployment, terrorists will try," Arbarchi says. "Our youth want a future, but they cannot see one."
Niger sits at the bottom of the UN's human development index and has the world's fastest growing population. More than half its people are under age 16. Climate instability is vulnerable to poor harvests; some 40 to 50 percent of the population suffers from malnutrition, according to UNICEF.
Through national media campaigns in Niger, Islamic associations have been calling on their countrymen not to be drawn in by extremist groups and fall into their rhetoric.
"Before, these associations were quiet, but now they are reacting to something they see as a threat," says an analyst in Niamey. "They sense extremism is growing in Niger."
Niger's small army took military assistance from the US and France, allowing drones to operate from Niamey. Despite Niger receiving combat support from Western countries, a group of well-trained fighters was still able to penetrate and damage two valuable, heavily protected areas.
Growing countersurveillance operations in the Sahel may help restrict Islamists' ability to mobilize and operate in large numbers, necessitating more covert tactics. "As the latest attacks in Niger demonstrate, the Islamists' considerable operational expertise and capabilities might show that the regional terrorism risk persists, especially to Western targets," Mr. Barclay says.
Across the Sahel in recent years, general anarchy has increased. The fall of Libya's Mr. Qaddafi helped load the desert with weapons and provided an unusual opportunity for Islamists and criminal networks alike.
"Drug trafficking is a huge problem," says a diplomat in Niamey. "Terrorists are building resources on trafficking – whether it be cigarettes, drugs, weapons, or people. AQIM needs money for jihad. But the traffickers need the terrorist networks to allow them to trade freely."
Without better surveillance of the region's borders to inoculate countries against the spread of terrorism, and a greater attempt to deal with the narcoterrorism that is motivating fighters with money rather than ideology, the risk of regional terrorism may persist.
In Mauritania and Burkina Faso, security forces now deal with jihadist kidnappers.
Nigeria faces new forms of terror as it fights a war with the Islamist insurgent group Boko Haram, a war that has claimed more than 3,600 lives over four years. Boko Haram fighters have been caught moving north to the Sahel for training. The Islamist radical group has shifted its focus from security forces and onto civilian targets, including schools and the mosques of Muslims deemed too moderate in their beliefs. The recent attacks by Boko Haram come as the Nigerian government started conducting in May an aggressive counter-terrorism strategy in the north of the country.
Nigeria is developing through oil enormous new sources of wealth and the disparity between rich and poor has become more visible and a greater sore point,
Guinea and Senegal seem more vulnerable to extremism and instability. Fundamentalist groups in Senegal are seizing on legitimate local grievances and giving them a religious spin, according to a report by the Institute for Security Studies.
Rhetoric has become more extreme among a significant minority, "notably in urban peripheries, among the youngest populations," states the report.
"There is a crucial difference between a more fundamentalist form of Islam and jihad," says a Muslim leader in Dakar. "We can't assume that one will lead to another."
"What causes the grievances is often the particular flavor of misgovernance in one area or another," Mr. Campbell says. "You've got the Islamist revival, which has a lot of support. It is by no means all radical. I do think an Islamist critique of governance resonates with a lot of people."