Al Qaeda failed to make good on threats to strike U.S. diplomatic outposts on this week's 9/11 anniversary, but in a new audio tape, the leader of the besieged terror network renewed his plea to followers to strike at American interests -- and to aim lower, if necessary, with individual acts of violence.
However, speeches by Ayman al-Zawahiri, who became Al Qaeda's "emir" or prince after the killing of Osama Bin Laden in 2011, are viewed as less inspiring to potential homegrown terrorists in the West to terrorism analysts including one who knew both al Qaeda leaders.
In the new Arabic-language tape, released Sept. 12 Zawahiri chortled over the "blessed" 2001 strikes that left thousands of Americans dead, as well as April's Boston Marathon bombings that killed just three Americans, which he claimed was proof of a Muslim "uprising."
"Keeping America in tension and anticipation only costs a few disparate attacks here and there," Zawahiri explained during his 72-minute recording. "These disparate strikes can be done by one brother or a few of the brothers."
That message was hardly new, even if the recording was.
Zawahiri endorsed acts of "individual jihad" two years ago at the peak of Yemeni-American cleric Anwar al-Awlaki's global influence as an al Qaeda in the Arabian Peninsula (AQAP) leader. Awlaki produced polished English-language speeches and the online magazine Inspire to encourage "lone wolf" terrorism. He was killed by a U.S. drone two years ago, months after bin Laden.
The new tape "will have an impact upon the jihad global community, but I doubt if it's going to be translated into violence," Noman Benotman of London counter-extremism firm Quilliam told ABC News on Friday.
In a new Quilliam report, Benotman, who as a Libyan jihadi knew both Zawahiri and bin Laden in Afghanistan before 9/11, assessed al Qaeda's global movement as "resurgent."
Zawahiri, an Egyptian pediatrician-turned-terrorist -- who speaks English fluently but hasn't taunted Americans in that language in many years -- lacks the credibility of the current generation of holy war commanders fighting in Syria, northern Mali, Afghanistan, Iraq, Somalia and Nigeria, said another terror expert.
"It only resonates with those who already sympathize with Zawahiri," Aaron Zelin, a researcher at the Washington Institute for Near-East policy, told ABC News. "The people that are convincing those on the ground are the ones actually fighting in Syria like Jabhat al-Nusra and the Islamic State of Iraq and Syria."
Inside the U.S., the FBI monitors approximately 100 individuals with Islamist extremist leanings, who have expressed a desire to commit violence, fund terror groups or otherwise communicate with known terrorists overseas, ABC News reported exclusively this week. That number isn't expected by the U.S. intelligence community to change in the coming years, according to intelligence and law enforcement sources.
Many of those are radicalized in part or motivated by videos, statements and jihadi chatrooms they found online, where al Qaeda's media wing, As Sahab, posts Zawahiri's speeches. But those messages resonate with westerners when they're from young, charismatic leaders like Alabama-reared ex-Shabaab commander Omar Hammami who speak in English -- not Arabic -- which Al Qaeda and its affiliates has increasingly employed in its propaganda, according to analysts.
In his 9/11 anniversary tape -- released the day after the actual anniversary -- Zawahiri urged al Qaeda's followers to "monitor and lie in wait and seize any opportunity to land a large strike on it, even if it takes years of patience for this."
Former FBI agent Clint Watts, a senior fellow at the Homeland Security Policy Institute, said the timing of the message could be significant.