Al-Qaida's deputy leader, Ayman al-Zawahiri, is second after Osama bin Laden on the F.B.I's list of most wanted terrorists.

This image made from an undated video broadcast Thursday, Aug. 4, 2005 on pan-Arab satellite channel Al-Jazeera, shows al-Qaida's Ayman al-Zawahri speaking with a Kalashnikov rifle propped up behind him at an undisclosed location

The Egyptian-born doctor has become the terrorist organization's most senior spokesman -appearing in a series of video, audio and print messages over the past three months.

In his most recent comment broadcast on videotape last week by Arabic broadcaster al-Jazeera, Zawahiri called on President Bush to confess that the United States has been defeated in Iraq and Afghanistan.

Ayman al-Zawahiri was indicted for his alleged involvement in the 1998 bombings of U.S. embassies in Dar es Salaam, Tanzania and Nairobi, Kenya.

He founded the Egyptian Islamic Jihad, a group that opposes the secular Egyptian government and seeks to overthrow it through violent means.

Zawahiri has been on the run since late 2001 after U.S.-led forces invaded Afghanistan.