Gunmen and a suicide bomber struck Monday, killing a religious leader and at least nine of his followers in Central Somalia.
The attack has been confirmed bt Somalia authorities.
Among those killed in the attack are women.
In an interview with Reuters news organisation, the terrorist group claimed responsibility for the attack.
The attack is further evidence that the group has not lost its ability to stage attacks on civilians in its gruesome campaign to usher into Somalia an order based on the strict interpretation of Sharia law.
In spite of the overwhelming military pressure that has been brought to bear on the group, Al-Shabaab controls some parts of Somalia, a demonstration of its strength.