WASHINGTON — Al Qaeda is recruiting children in Iraq to join the ranks of the terrorist organization, according to a new video released by the American military.

The video, which was captured in a raid in late last year in Diyalla province and posted to the Web yesterday, depicts children in ski masks kidnapping a grown man on a bicycle; sitting in a circle surrounding firearms singing Qaeda songs, and storming a room with bound adult hostages and waving guns at their heads.

Yesterday a spokesman for Multinational Forces Iraq, Rear Admiral Gregory Smith said, “This is not the first time we’ve observed such material but the volume and content was the most significant and disturbing we have found to date.”

Admiral Smith said the military believed the videos were probably for recruiting purposes and were likely staged. Nonetheless the message for Iraqis still reeling from suicide bomb attacks carried out last week by two women with Down’s Syndrome is chilling.

The military spokesman yesterday said one implication of the new video showing the children is that there are families headed by Qaeda operatives and these are the lessons imparted to the next generation.

“Clearly there are families in which the adult males are part of Al Qaeda and you would assume that those children are growing up in that environment that would, unfortunately, produce the next generation of Al Qaeda,” he said. The military has collected volumes of evidence displaying Qaeda’s cruelty. Last year, Multinational Forces in Iraq released illustrated manuals instructing the group’s interrogators how to torture the detained.

At the press conference yesterday, Mr. Smith also said American forces at a separate location in Diyalla had captured a script for a propaganda film depicting children placing roadside bombs, murdering individuals, and interrogating them.

As Qaeda turns to the disabled and children to replenish its ranks, the military says overall Iraq’s Sunni tribes have routed the group in the last year. Even Al Qaeda’s second in command chastised the Iraq franchise last year for losing ground in the battle for Iraq.

In Pakistan yesterday, a group claiming to speak for Al Qaeda released a Web video vowing revenge for an air strike last month that allegedly claimed one of the group’s senior commanders, Sheikh Abu Laith al-Libi. In the video, Mustafa Abu al Yazid said, “The men he trained … will not rest until they avenge him and realize his aspirations and hopes, God willing.” He added, “The enemies of God were unable to confront Sheikh Abu Laith al-Libi on the battlefield or to fight him as equals as they are too cowardly for that.”

The air strike against al Libi took place in the renegade North Waziristan province of Pakistan on the border with Afghanistan. That province is effectively a sanctuary for Al Qaeda. On Tuesday, the director for national intelligence, Michael McConnell, conceded that Al Qaeda had rebuilt much of its infrastructure in this region.