Boko Haram's loyalty pledge to the Islamic State group has raised fears of further Islamic State alliances in sub-Saharan Africa. Terrorism experts however, say the continent's most powerful extremist force, Somalia's al-Shabab, is unlikely to go down the same path.
Al-Shabab has deep ties to al-Qaida -- the Islamic State group's main rival -- going back to the 1990's, when the terrorist network trained some of al-Shabab's most prominent leaders at camps in Afghanistan and Pakistan.
So far, there has been no direct contact between the leaders of al-Shabab and the militant group, at least publicly. Observers believe supporters of the two organizations are talking. Last week, a new video released by al-Shabab's media wing was first posted on an Islamic State-only file sharing site.
Still, this is not firm evidence of collaboration. Experts like Abdiaziz Alas Artan, a Cairo-based scholar of militant organizations, have trouble envisioning an alliance between the groups.
“At this time it’s not easy for Al-Shabab to join ISIS," Artan said. "First, al-Shabab has given allegiance to al-Qaida, the parent organization, and to throw that away will be difficult.
"Secondly, al-Shabab feels it’s the older organization, the more senior one that has the priority, and if anyone has to move, [Islamic State] has to ... for them to downgrade and to join a group that, not just emerged just yesterday, but one that also disobeyed al-Qaida central, is going to be difficult.”
In 2012, al-Shabab merged with al-Qaida. Somalia expert Roland Marchal of the National Center for Scientific Research in Paris said al-Shabab has forged deep links not only with al-Qaida central, but also to its powerful Yemen-based affiliate, al-Qaida in the Arabian Peninsula.
“The linkage between the two has become more systemic or certainly deeper than it was any time before," Marchal said. "And it’s not only an issue of ideology or personal relations, it’s something that goes much deeper into the organization of both groups.”
But at least one prominent al-Shabab supporter is pushing for a switch in alliances. In an audio message posted online this week, Kenyan cleric Sheikh Hassan Hussein, also known as "Abu Salman," said there are no religious grounds for opposing the leader of Islamic State.
Salman hinted there is reluctance within al-Shabab to leave al-Qaida. "Those jihadists who want to recognize Mullah Omar as Amirul Mi'miniin (the Emir of Muslims) are avoiding recognizing Abu Bakr Al-Baghdadi instead," he said.
The rise of the Islamic State group has lured militant organizations at a time when al-Qaida leaders are severely crippled by U.S. intelligence operations. The group has attracted thousands of jihadists from around the world, including many from the Middle East, Europe and North America.
In the lower militancy ranks, it’s becoming clearer that young fighters are excited by successes of the Islamic State group. Marchal said even though the al-Shabab leadership has affinity with al-Qaida, some members see Islamic State militants as more practical than al-Qaida.
"They said what is nice with ISIS is the fact whatever area they take under control they try to build something, they try at least to build the first steps of an Islamic state, while with al-Qaida, we will be fighting for one century before we defeat all our enemies," said Marchal.
"So for what I have been told, many in the military section of al-Shabab are keener towards ISIS while the Amniyat [the security force] and the political leadership is much closer to al-Qaida.”
Unlike al-Shabab, Boko Haram was free of any allegiance before committing to the Islamic State group -- an important difference, experts said.
Whatever decision al-Shabab takes will be a strategic one, not ideological, analysts argue. They say that's because al-Qaida and the Islamic State group come from the same side of the militancy spectrum -- both are violent extremist groups that want to set up a caliphate and impose a strict form of sharia.
“The ideology is similar, the jihadi ideology is similar," Artan said. "The only difference is [Islamic State's] rise was driven by anti-Shi'ite [ideology] while the rest of al-Qaida is anti-West driven.”
Then there is the issue of opportunism. Some observers believe Boko Haram may have taken the step to join the militants of the Islamic State because, in part, it saw an chance to increase recruitment and fundraising for their organization.
One politician in Somalia -- former defense minister Abdihakim Haji Mohamud Fiqi -- thinks al-Shabab also may turn opportunistic after military setbacks at the hands of the African Union mission in Somalia [AMISOM] and the Somali government.
"In my opinion it’s really possible," said Fiqi, "because al-Shabab is desperate ... they have no hope today that they can win this terrorism war, they can do anything they can to get support, such as [team up] with IS or Boko Haram, so it’s possible."
Al-Shabab has lost most of its territory to AMISOM and many of its leaders to U.S. drone strikes over the past four years. One such strike killed the group's emir, Ahmed Godane, in September 2014.
Another strike earlier this this month killed Adan Ahmed Isak, better known as Adan Garaar, who allegedly played a role in planning the deadly 2013 attack on Nairobi's Westgate shopping mall.
Fiqi added, however, that he does not believe al-Shabab can get tangible help by switching its alliance.
"We know the situation of ISIS. There are many nations that are in alliance against ISIS, and there is no hope they can support al-Shabab economically or militarily," he said.
But even with the Islamic State group on the defensive, it still has secured alliances elsewhere in Africa, from Egypt to Libya, and now Nigeria.
