The station said that bin Laden also is shown greeting some of the hijackers, although their faces were not clear and it was not immediately known which are purportedly shown.

The video included the last wills and testaments of hijackers Wail al-Shehri and Hamza al-Ghamdi.

Al-Jazeera did not say how it obtained the video, which was produced by As-Sahab, al-Qaida's media branch. Islamic militant Web forums said the entire video would be posted soon on the Internet. Such advertisements in the past have come a day or two before the video appears on the Web.

Thursday's was the fourth in a series of long videos that al-Qaida has put out to memorialize the Sept. 11, 2001, attacks on the Pentagon and World Trade Center, said Ben Venzke, head of IntelCenter, a private U.S. company that monitors militant message traffic and provides counterterrorism intelligence services for the American government.

The previous ones were issued in April and September 2002 and September 2003, each showing video from the planning of the suicide hijackings and farewell statements from some of the hijackers, Venzke said.

In the latest video, bin Laden is shown sitting outside with his former lieutenant Mohammed Atef and Ramzi Binalshibh, another suspected planner of the Sept. 11 attacks.

Venzke said the scenes had not been previously broadcast.

Atef, also known as Abu Hafs al-Masri, was killed by a U.S. airstrike in Afghanistan in 2001. Binalshibh was captured four years ago in Pakistan and is in U.S. custody. President Bush announced plans to put him on military trial.

The video shows bin Laden in a dark robe and white headgear, strolling through the camp and greeting dozens of followers, some masked, and many carrying automatic weapons. A voice-over narration praises the fighters and refers to the camp being "on the soil of Kandahar" - a city in southern Afghanistan.

The footage shows scenes of training at the camp. Masked militants perform martial-arts kicks or learn how to break the hold of someone who grabs them from behind. Several militants are shown practicing with fold-out knives.

Venzke said the footage was part of a video he expected would be more than an hour long, based on previous releases.

He said the full version of the video was believed to include a message from Azzam al-Amriki, the nom de guerre of Adam Yehiye Gadahn, an American who the FBI says has associated with al-Qaida. Gadahn appeared in an al-Qaida video released last week, in which he called on Americans to convert to Islam.

The full video also likely includes messages from bin Laden or his deputy, Ayman al-Zawahri, though they may not be new, Venzke said, without elaborating on why he believed that.

"They produce long videos like these not just for 9/11, but for any significant events they feel warrant their attention," Venzke said.

One aim is to boost recruitment, but such videos have other purposes - "to speak to their supporters, to raise morale within their own group, to facilitate fundraising, and to serve as a psychological attack," he said.

The footage also shows glimpses of daily life in the camp, with men chopping wood and cutting up vegetables for dinner.

Al-Shehri and al-Ghamdi are each shown speaking to the camera, their images superimposed over pictures of the crumbling World Trade Center towers and the burning Pentagon, as well as a model of a passenger jet.

They both say Muslims must stand up and fight the West.

"If jihad now is not an obligation (on Muslims), when will it be?" said al-Shehri, pointing to attacks on Muslims in Bosnia, Afghanistan and Chechnya.

"If we are content with being humiliated and inclined to comfort, the tooth of the enemy will stretch from Jerusalem to Mecca, and then everyone will regret on a day when regret is of no use," al-Ghamdi said.