Al Qaeda's No. 2 leader claimed in an audiotape released Friday that five years of U.S. involvement in Iraq brought only defeat, and said President Bush will be forced to pass the problem to his successor.

Ayman al-Zawahiri alleged that by heeding advice of his top commanders in Iraq and guaranteeing a heavy American military presence after July, Bush was "covering up for the failure" of his Iraq policies.

"If the American forces leave, they will lose everything. And if they stay, they will bleed to death," he argued.

The authenticity of the 16-minute recording, posted on a Web site known for militant messaging, could not be independently verified. But it carried the logo of Al Qaeda's media wing and was the second in April attributed to the terror network's chief strategist.

He called for Muslim support of jihad in Iraq, and for backing Al Qaeda's affiliate there, the so-called Islamic State of Iraq.

Al-Zawahiri also blasted Sunni fighters who switched sides and joined the American push to pacify Sunni areas of Iraq, the so-called "Awakening Councils."

"Weren't these Awakening (Councils) supposed to hasten the departure of the American forces, or are these Awakenings in need of someone to defend them and protect them," al-Zawahiri asked.

He also reiterated a recent statement allegedly by Osama bin Laden, that from Iraq the mujahideen will launch a fight to "liberate" Jerusalem.

"Iraq nowadays is the most important battlefield on which our mujahedeen are waging a war against the forces of the Zionist-Christian Crusade," al-Zawahiri said. "Therefore, supporting the mujahideen in Iraq and especially the Islamic State of Iraq is a most important duty."

Al-Zawahiri also slammed anti-American Shiite cleric Muqtada al-Sadr, who has ordered his militia to halt attacks on American and Iraqi forces. He "has become the laughing stock of the world" and is a "toy" in Iran's hands, he said.

Al-Zawahiri also criticized the "exploitation of Muslims" in Egypt, his homeland, as well as the plight of Palestinians in the Israel-besieged Gaza.