The Shebab militant group claimed responsibility for the September 2013 massacre in the Kenyan capital's Westgate mall, a four-day seige in which at least 67 people were killed
Nairobi (AFP) - The new leader of Somalia's Al-Qaeda-linked Shebab rebels is thought to be a devout and ruthless hardliner and one of the most trusted lieutenants of the group's late chief, experts said Sunday.
The Shebab acknowledged in a statement on Saturday that former leader Ahmed Abdi Godane had died in a US air strike on Monday. The group named Ahmad Umar, also known as Abu Ubaidah, as its new head, while also stating it remained a part of Al-Qaeda's global Islamist network.
Very little is known about Abu Ubaidah, and a senior Shebab official only described him as having been very close to Godane, a hardliner who had overseen the group's transformation from local insurgency to major regional guerrilla threat.
"Avenging the death of our scholars and leaders is a binding obligation on our shoulders that we will never relinquish nor forget no matter how long it takes," the Shebab statement said.
"By the permission of Allah, you will surely taste the bitter consequences of your actions," it added, while also renewing a pledge of allegiance to Al-Qaeda chief Ayman al-Zawahiri, Osama bin Laden's successor.
Sources close to the Shebab said Abu Ubaidah was thought to have been involved in a major internal purge that took place last year, when Godane eliminated several key rivals including a commander who had been tipped as a potential successor.
Abu Ubaidah is also thought to have had a hand in the last year's killing of Alabama-born Omar Hammami -- better known as Al-Amriki or "the American" -- who was one of the most prominent foreigners fighting in Somalia but who fell out with Godane.
- 'Clan dynamics' -
According to Roland Marchal a researcher at France's CNRS, it is unlikely that the group managed to assemble all its top commanders to discuss the succession because of fears of further air strikes.
"This signifies that not everybody was consulted. It is possible that Abu Ubaidah will not be there for a long period, just enough time for them to reorganise themselves. It is not out of the question that he is just an interim leader," Marchal said.
According to an intelligence source, Abu Ubaidah is believed to have played a role in the Shebab's most shadowy and feared wing, the clandestine internal secret service known as "Amniyat", which Godane set up to maintain discipline and expose rivals and informers.
The source said the new leader is thought to be in his early 40s and from the southern port town of Kismayo, which is currently held by Kenyan troops fighting with the African Union's AMISOM force. He also once served as the Shebab's governor in the Bay and Bakool region.
But Marchal said Abu Ubaidah was also from a minority Somali clan -- which could cause tensions related to the complex clan dynamics that are still at play beneath the Shebab's veneer of being an Islamist organisation.
"The Shebab is also an organisation and not just one leader. Abu Ubaidah is not known as someone who deals with the political economy of the organisation," including sources of revenue that fund its army estimated to number 5,000 to 7,000 fighters, Marchal said.
Disinformation cannot be ruled out, another intelligence source said, explaining that the pressure of constant surveillance and drone strikes means the Shebab may even have named a "simple figurehead", a "ghost" or "given a pseudonym" as a deliberate tactic to protect their real hierarchy.
Godane himself took over the leadership of the Shebab in 2008 after then military leader Adan Hashi Ayro was killed by a US missile attack.