JOHANNESBURG — The Westgate Mall attack in Kenya threw the spotlight on Al Shabab, the Somalia-based group of Islamist militants that claimed responsibility. But its relationship with Al Hijra, a relatively obscure cell of extremists in Kenya, represents what terrorism analysts say is a worrying trend in Africa: an increase in collaboration among religious radicals across borders and vast, poorly policed regions.
For now, analysts say, this networking lets militant groups in Africa aid one another in the face of pressure from security forces, but does not entail a coordinated, continent-wide strategy that could sideline the local agendas they hold dear. The fear is that the more these groups talk to one another, the more people they will kill as they fight efforts to contain them.
‘‘It is the growing connectivity between some of these groups that is starting to form a network across Africa which could be very, very dangerous,’’ General Carter Ham said in December, when he was chief of the US military’s Africa command. Ham, who has retired, warned at the time that Al Shabab and other like-minded outfits were increasingly working together in the fields of training, funding, and weapons.
No evidence has yet emerged that shows such regional networking played a role in the Sept. 21 Nairobi mall attack that killed at least 67 people. But some observers believe Al Hijra may have played a role in the mall attack, noting its close ties to Somali militants.
‘‘It is really a close affiliate, a Kenyan part of Al Shabab,’’ said Stig Jarle Hansen, a Norwegian academic who has written a book about Al Shabab.
Al Shabab, which has pledged allegiance to Al Qaeda, said the assault was payback for Kenya’s military role in pushing back Islamist fighters in neighboring Somalia. The Kenyan police, meanwhile, may be going after suspected Al Hijra members at home.
Al Hijra has been ‘‘plagued by unexplained killings, disappearances, continuous ‘catch and release’ arrest raids, and operational disruptions,’’ the United Nations said in a July report on Somalia and Eritrea.
Human rights groups blame Kenyan police for the forced disappearances and executions.
‘‘Al Hijra is striving to regain the initiative, in part through its fighters in Somalia returning to conduct new and more complex operations and through strengthening its ties to other groups in the region,’’ the UN report said.
It said Al Hijra was building links with extremists in Tanzania, as well as Al Shabab affiliates in Rwanda and Burundi.