Leaders of 9/11 shown joking in video

Mohamed Atta, leader of the 11 September hijackers, is shown laughing and joking while filming his "martyrdom testament" while others involved in the attacks are shown listening to a speech by Osama bin Laden, in a newly released video.

The footage was taken at a camp used by Bin Laden and senior al-Qa'ida figures in Afghanistan in January 2000 when some of the final details of the plan for the New York attack are said to have been put together. Atta, who flew one of the planes into the twin towers, is seen alongside Ziad Jarrah, who piloted UA93 before it crashed into a field in Pennsylvania after passengers stormed the flight deck.

It is the first time the two hijackers have been shown together. They seem to be studying the testaments which were due to be made public after their deaths.

Also pictured, among the Bin Laden group, is Ramzi Bin al-Shibh, said to be the co-ordinator of 11 September and now at Guantanamo Bay, and the al-Qai'da leader's bodyguard, Abu Jandal. Jailed in Yemen until 2003, Abu Jandal said he carried a second gun to be used to shoot Bin Laden if he was in danger of capture.

The tape, thought to have been obtained by Yosri Fouda, a journalist with al-Jazeera television, is mute and, according to US security sources, lip readers have not been able to decipher what is being said.

The filming is said to have taken place at Tarnak farm, near Kandahar, where the CIA plotted to kidnap Bin Laden in 1998. Atta, son of an Egyptian lawyer, disappeared from his home in Hamburg in January 2000. Jarrah, from a middle-class Lebanese family, had also studied in Germany.

In the video, the two men are seen sitting on the floor with a Kalashnikov rifle propped beside them.