Al-Qaeda leader Ayman al-Zawahiri has called for small-scale attacks inside the United States to "bleed America economically," and claimed an indirect connection to the Boston Marathon bombings, according to the SITE monitoring service that tracks al-Qaeda statements.
In an audio speech released online a day after the 12th anniversary of the 9/11 attacks, Zawahiri said attacks "by one brother or a few of the brothers" would weaken the U.S. economy by triggering big spending on security, SITE reported.
Analysts said the al-Qaeda leader's words may reflect a trend away from high-casualty attacks like 9/11.
Aymenn Jawad al-Tamimi, a Shillman-Ginsburg Fellow at the Middle East Forum, a conservative think tank based in Washinton, D.C., said the U.S. embassy closings in August due to an al-Qaeda in the Arabian Peninsula (AQAP) threat exemplify the economic warfare tactic.
Al-Tamimi, who writes about al-Qaeda for Jihadology and other online publications, saw Zawahiri's call for small-scale attacks as a response to the U.S. shutting down 21 embassies due to the "mere threat of attack."
"Zawahiri can see that Western nations tend to go into an economically costly, protective over-reaction" in response to such threats, Al-Tamimi said.
Egyptian-born Zawahiri said: "We should bleed America economically by provoking it to continue in its massive expenditure on its security."
Keeping the United States in such a state of tension and anticipation only required a few disparate attacks "here and there," he said.
Western security chiefs have warned that radicalized "lone wolves" who might have had no direct contact with al-Qaeda posed as great a risk as those who carried out complex plots like the 9/11 attacks, which killed almost 3,000 people.
The Boston Marathon bombing in April, which left three people dead and injured 264, is the most prominent example in recent memory of a "lone wolf" attack.
Nevertheless, Zawahiri sought to paint the bombing as part of al-Qaeda's violent transnational campaign against U.S. interests.
"The Boston incident confirms to the Americans ... that they are not facing individuals, organizations or groups, but they are facing an uprising Ummah (community), that rose in jihad to defend its soul, dignity and capabilities," Zawahiri said. "What the American regime refuses to admit is that al-Qaeda was a message before it was an organization."
Al-Tamimi said Zawihiri's remarks could potentially provoke attacks.
"Any person could buy into this narrative and these ideas without receiving formal training or membership of an organized armed group, but the ideas are still ultimately traceable to pro-al-Qaeda preachers and its leadership."
Though his whereabouts are unknown, many security specialists believe Zawahiri to be living in the Pakistan-Afghanistan border area.