The speaker on the tape, aired by Al Jazeera and Al Arabiya channels, also urged Muslims around the world to fight what Zawahri called the Christian-Zionist crusade "aimed at eradicating Islam and Muslims."

It was not possible to verify the authenticity of the tape, which appeared to be recent because it blasted India for hosting Israeli Prime Minister Ariel Sharon earlier this month.

It was the latest in a series of audio and video tapes released to the media since the September 11, 2001 attacks on US cities for which Osama bin Laden's al-Qaeda is widely blamed. Zawahri is bin-Laden's right-hand man.

The voice on the tape blasted the Pakistani president for aiding Washington in its war in Afghanistan against al-Qaeda and the Taliban, and accused him of planning to send Muslim troops to Iraq "to be killed instead of American soldiers."

"Muslims in Pakistan must unite to oust this traitor and put in place a loyal leadership in Pakistan which defends Islam and Muslims," the speaker said.

Pakistani security forces have cooperated closely with U.S. forces to hunt for bin Laden and other al Qaeda members in border areas where many believe they are hiding.