Al Qaeda issues message about September 11th
September 13, 2013 -- Updated 1033 GMT (1833 HKT)
Al Qaeda leader Ayman al-Zawahiri, pictured here in a 2006 file photograph, has called for fresh attacks on the United States.
- To commemorate 9/11, al Qaeda's leader issued new threats
- Ayman al-Zawahiri called on his followers to "land a large strike"
- He named the Boston Marathon bombings as an example
- Drone strikes have weakened al Qaeda in Yemen
(CNN) -- Americans commemorated this week the loss of those who died at the hands of al Qaeda terrorists on September 11, 2001. Their leader chimed in a day later with new threats against the United States.
Ayman al-Zawahiri called on his followers in an audio message posted on the Internet on Thursday to "land a large strike on it, even if it takes years of patience for this."
9/11 anniversary: 'Our hearts still ache,' Obama says
Al-Zawahiri has headed al Qaeda, since a U.S. military operation killed his predecessor and al Qaeda's founder, Osama bin Laden, in May 2011 in Pakistan.
In his message, he claimed victory against the United States in Iraq and Afghanistan. He called on terrorists to continue the battle on American soil.
Al Qaeda leader orders immediate action
Al-Zawahiri named the Boston Marathon bombings on April 15 as an example of such an attack.
Read more: Jihadist terrorism in America since 9/11
He encouraged his followers to provoke the United States into spending more on security, in order to "bleed America economically."
In August the Obama administration closed 19 embassies and consulates across the Middle East and North Africa after intercepting communications between al Qaeda leaders indicating possible strikes on U.S. interests.
In a message between al-Zawahiri and a top ally in Yemen, Nasir al-Wuhayshi, the leader of Al Qaeda in the Arabian Peninsula, the terror chief told the Yemeni commander to "do something," which U.S. officials inferred to mean an attack.
In his audio message Thursday, Zawahiri also claimed victory over the United States in Yemen.
But extensive drone attacks there allegedly carried out by the United States over the past two years have whittled away at al Qaeda's infrastructure and killed key leaders, diminishing its ability to carry out attacks.
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