Hamza bin Laden, son of al-Qaeda's slain founder Osama bin Laden, in an undated audio message urged youth to join the Yemen-based al-Qaeda in the Arabian Peninsula (AQAP) to "gain the necessary experience" to fight, according to SITE.

Classified by the United States as the network´s deadliest franchise, AQAP was formed in January 2009 as a merger of the Yemeni and Saudi branches of al-Qaeda. Yemen is the ancestral home of Saudi-born Osama bin Laden, who was killed in Pakistan in 2011 by an elite team of US Navy SEALS after a decade on the run.

US intelligence officials have said that 23-year-old Hamza was the favourite son of the 9/11 mastermind who had been grooming him to take over as al-Qaeda´s leader.

On the occasion of the fifth anniversary of Osama bin Laden´s death, experts have noted Hamza´s increasing prominence among jihadists in comparison to that of Egyptian Al-Qaeda leader Ayman al-Zawahiri.