In it, he claims a Libyan terror organization has linked arms with al Qaeda to overthrow Libya's political leaders, in retaliation for what it says is the African nation's closer ties to the West.
CBS News research on Jamaa Islamiya of Libya shows that most of that organization's leadership are in Libyan prisons, and that most of its leaders who have escaped prison have fled to Afghanistan.
Their presence in the same region where authorities believe Zawahiri to be at this stage helps to explain this new claim of linkage between the groups. Yet prior to the audio tape's release, CBS News has found no evidence of any link between Zawahiri and Jamaa Islamiya in Libya.
In the tape, which surfaced today on a Web site, Zawahiri was harshly critical of the Libyan leader, branding him an enemy of Islam, and threatens a wave of attacks against Libya because of its improved relations with the United States.
In the 28-minute-long recording, titled "Unity of the Ranks," Zawahiri announced that the group Jamaa Islamiya in Libya has joined al Qaeda, and urged the Mujahideen in North Africa to topple the leaders of Libya, Tunisia, Algeria and Morocco.
"Today, with the grace of Allah, the Muslim Ummah witnesses a good and positive move … with some of the finest members of the Combatant Jamaa Islamiya in Libya announcing they've joined al-Qaeda to follow on the footsteps of their brothers," Zawahiri said in the tape.
Zawahiri once again slammed Fatah, saying that its leadership has turned the movement into a branch of the CIA, and a department of the Mossad. He urged members of al Aqsa Martyrs brigades to rebel against their political leaders, put their trust in Allah, and embrace Jihad in Palestine and elsewhere.
He then introduced Libyan Abu Laith al Libi, another al Qaeda leader who has been in charge of the training camp in Afghanistan.
Al Libi launched into a scathing attack on the Libyan regime, and slammed Moammar Gadhafi, "The Tyrant of Libya," for allowing the "Crusaders" led by the United States to turn Libya into yet another base from which to wage their campaign against Muslims in North Africa.
Al Libi then announced that the Jamaa Islamiya of Libya has joined the ranks of al Qaeda. "At the Jamaa Islamiyah, we hereby declare that we are joining al Qaeda … To become loyal soldiers who will lift the banner of monotheism and Jihad and follow the steps of our leaders, and on top of them Sheikh Osama bin Laden, may Allah protect him," al Libi said.
Al-Libi went on to say that the group, under this new status, will be closely cooperating with al Qaeda in the Islamic Maghreb (Algeria).