The head of Syria's Nusra Front militant group mourned the death of al Qaeda's deputy leader in an audio message that underlined the organizations' close relationship and appeared to counter recent reports that it might split from the global network. Nusra is al Qaeda's wing in Syria, but sources close to and in the organization told Reuters this year it was considering distancing itself from the parent group so that it could attract funding from a wider range of donors. Nusra is one of the most powerful forces fighting Syrian President Bashar al-Assad in an increasingly complex conflict.