Washington: Al Qaida leader Osama Bin Laden appeared on a new videotape, stressing the importance of martyrdom for Muslim causes.

CNN said on Sunday that the 40-minute videotape was intercepted before it was to appear on several Islamist websites.

"So be alert, be wise and think. What is this status that the best of mankind wished for himself? He wished to be a martyr," Bin Laden said.

During the 50-second message, Bin Laden appeared to address an audience below him, which is unseen. A bodyguard stood directly behind him.

The Al Qaida leader was one of several men appearing and speaking on the tape. Slain Al Qaida leader in Iraq Abu Musab Al Zarqawi also appeared in the tape.

CNN senior editor Octavia Nasr said the videotape was made in the last four weeks but the clips appear to be old. The authenticity of the tape could not be immediately verified.