The tape, which aired on the al-Jazeera network, showed Zawahiri also calling on al-Qaeda fighters to attack oil installations in Islamic countries “because most of the revenues of this oil go to the enemies of Islam”.
Al-Jazeera said the tape, which was undated, first appeared on a website.
“Al-Qaeda for holy war is still, thanks to God, a base for jihad. Its prince Osama bin Laden, may God protect him, still leads the jihad,” he said on the tape.
“All the lies that (US President George W) Bush tries to delude the Americans with, saying that he destroyed half, or three quarters of al-Qaeda are but nonsense merely in his own head,” said Zawahiri.
He said al-Qaeda is “a popular organisation confronting a new Crusader Zionist Western and Israeli campaign, in defence of all violated Muslim lands.”
He said the US coalition in Iraq is “receiving blows every day”, while the Iraqi government is “begging Americans not to leave because they know the day Americans leave is the day they are finished.”
Bin Laden is the head of the al-Qaeda terrorism network that claimed responsibility for the September 11, 2001, attacks in the United States, along with other incidents.
Zawahiri, who is shown wearing a black turban and white robe and speaking against a white background to an off-camera interviewer, said the video was to mark the fourth anniversary of the September 11 attacks.
He, along with Bin Laden and other key militants, are believed to be hiding in the remote and mountainous border region between Pakistan and Afghanistan.
Zawahiri last appeared in a video broadcast by al-Jazeera in October when he urged Muslims to help Pakistan’s earthquake victims.
An eye surgeon by training, he is considered al-Qaeda’s chief ideologue, and some experts believe he was the operational brains behind 9/11.