In his message Thursday, the day after the 12th anniversary of the terrorist attacks on the United States, Zawahiri also claimed victory against the United States in Iraq, Afghanistan and Yemen, CNN reported.
Zawahiri has led al-Qaida since a U.S. military operation killed the terror organization's founder Osama bin Laden in May 2011 in Pakistan.
The terror chief's remarks were in a 60-minute-plus audio message released on jihadi blogs and produced by al-Qaida's media wing, CBS News reported.
"To keep up the hemorrhage in America's security and military spending, we need to keep the United States on a constant state of alert about where and when the next strike will blow," Zawahiri said. "Keeping America on its guards only requires from us scattered strikes here and there."
Zawahri's message focused mainly on encouraging so-called lone wolf attacks, but he also urged more strikes on the level of the Sept. 11, 2001, attacks which he said were a punishment for the United States' "continuous war on Islam and Muslims."
He also called on Muslims to kidnap westerners to swap for Muslim prisoners held in the West, CBS News said.
In August, 19 U.S. diplomatic facilities across the Middle East and North Africa were closed after the interception of communications between al-Qaida leaders indicating possible strikes on U.S. interests.
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