The Bush administration said Sunday it verified that an audio message posted on the Internet is in Usama bin Laden's voice.

The Al Qaeda head is heard endorsing the terrorist network's new leader in Iraq and warning Shiites there against collaborating with the United States against Sunni insurgents.

After a technical analysis, the CIA said it determined that the voice heard on the tape is bin Laden's.

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In Saturday's message, bin Laden also warned nations not to send troops to Somalia, where Islamic militants have taken control of the capital and much of the south.

It was his fifth audio message this year and second in two days. On Friday, bin Laden paid tribute to Abu Musab al-Zarqawi, the head of Al Qaeda's operations in Iraq who was killed in a U.S. airstrike on June 7.