The recording provides fresh evidence of ominous changes underway within the embattled organisation that declared war against the West nearly two decades ago, according to US, European and Middle Eastern intelligence officials and terrorism experts. Decimated by US military strikes and overshadowed for years by its terrorist rival, the Islamic State, al-Qaeda appears to be signalling the start of a violent new chapter in the group’s history, led by a new bin Laden - one who has vowed to seek revenge for his father’s death.

Encouraged by the Islamic State’s setbacks in Iraq and Syria, al-Qaeda is making a play for the allegiance of the Islamic State’s disaffected followers as well as legions of sympathisers around the world, analysts say.

“Al-Qaeda is trying to use the moment - [with] Daesh being under attack - to offer jihadists a new alternative,” said a Middle Eastern security official, speaking on the condition of anonymity to discuss counterterrorism assessments and using the Arabic acronym for the Islamic State.

“And what could be more effective than a bin Laden?”

Hamza bin Laden is hardly new to the Islamist militant world. His coronation as a terrorist figurehead has been underway since at least 2015, when longtime al-Qaeda leader Ayman al-Zawahiri introduced him in a video message as a “lion from the den” of bin Laden’s terrorist network. But in recent months, he has been promoted as a rising star on pro al-Qaeda websites, with audio recordings from him urging followers to carry out attacks or commenting on current events.

“Hamza is the most charismatic and potent individual in the next generation of jihadis simply because of his lineage and history,” said Bruce Riedel, who spent 30 years in the CIA and is now director of the Brookings Institution’s Intelligence Project.

“At a time when Zawahiri and al-Baghdadi seem to be fading, Hamza is the heir apparent.” Abu Bakr al-Baghdadi is the Islamic State’s leader.

But Hamza bin Laden is not advocating his father’s style of jihad. Osama bin Laden was notorious for his ambitious, carefully planned terrorist operations, directed by al-Qaeda’s generals and aimed at strategic targets. His son, by contrast, urges followers to seize any opportunity to strike at Jewish interests, Americans, Europeans and pro-Western Muslims, using whatever weapon happens to be available.

“It is not necessary that it should be a military tool,” he says in the May 13 recording. “If you are able to pick a firearm, well and good; if not, the options are many.”

Strikingly, for a man who aspires to be the jihadist world’s next rock star, Hamza bin Laden insists on keeping most of his personal details hidden from public view. Even his face.

No confirmed photographs exist of the young terrorist since his boyhood, when he was portrayed multiple times as an adoring son posing with his famous father. He is believed to be married, with at least two children, and he lived for a time in the tribal region of northwestern Pakistan, although his whereabouts are unknown.

His refusal to allow his image to be published may reflect a well-founded concern about his personal safety, but it complicates the militants’ task of making him a terrorist icon, said Steven Stalinsky, executive director of the Middle East Media Research Institute, a Washington-based non-profit organization that monitors Islamist militancy on social media.

What is known about Hamza bin Laden comes from his numerous recordings as well as intelligence reports and scores of documents seized during the 2011 raid by U.S. Navy SEALS on Osama bin Laden’s safe house in Abbottabad, Pakistan. Included in the document trove were personal letters from Hamza to his father, as well as written instructions from the elder bin Laden to his aides on how Hamza was to be educated and provided for.

Hamza bin Laden’s persistent calls for self-directed, lonewolf attacks against a wide array of targets appears to be borrowing directly from the playbook of the Islamic State, which has fostered a kind of Everyman’s jihad that does not depend on instructions or permission from higher-ups.

Watch: Osama bin Laden and al-Qaeda

His internet postings have lauded Army psychiatrist and convicted Fort Hood shooter Nidal Hasan, who murdered 13 people in a rampage on the base in Texas in 2009; as well as the two Britons of Nigerian descent who hacked British soldier Lee Rigby to death on a street outside his London barracks in 2013.

None of those assailants were known al-Qaeda members. Yet, by applauding such attacks, Hamza bin Laden appears to associate himself with a more aggressive style of terrorism that appeals to young Islamist militants, analysts and experts said. Such messages also convey an impression of a terrorist network that, while battered, is far from defeated, said Bruce Hoffman, a former US adviser on counterterrorism and director of Georgetown University’s Centre for Security Studies.

“He brings assurance that, even though al-Qaeda has been hammered in recent years, it’s still in good hands, with a junior bin Laden who is ideally situated to carry on the struggle,” Hoffman said.

“Since a very young age, Hamza bin Laden wanted to follow in his father’s footsteps. And from al-Qaeda’s perspective, now is the critical time for him to come of age and assume the reins of authority.”