They use a complex chain of human couriers, rather than intercept-prone electronics, to get out their messages. Al-Zawahri has issued 10 video or audio messages this year. Bin Laden — last seen in video in October 2004 — has released five audio messages during 2006.

Among the messages was a June 30 tribute to al-Qaida in Iraq leader Abu Musab al-Zarqawi, killed north of Baghdad on June 7, and another soon afterward endorsing al-Zarqawi's successor.

Although Pakistan claims to have reduced al-Qaida's leaders to symbols, Pakistani intelligence says its agents have heard that the alleged British-based scheme to bomb trans-Atlantic jetliners was blessed by al-Zawahri. If true, that would mean Afghanistan remains the headwaters of the world's most feared terrorist movement nearly five years after 3,000 people were killed in New York, Washington and Pennsylvania.

"There's a little bit of whistling past the graveyard when we say the organization (al-Qaida) is broken," said Scheuer.

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Associated Press writers Munir Ahmad in Islamabad and Riaz Khan in Peshawar, Pakistan, contributed to this report. Paul Garwood reported from Kabul and Kunar province, Afghanistan. Matthew Pennington reported from Islamabad and Peshawar.