Osama Bin Laden is said to be preparing to release a video message to the American people to coincide with the sixth anniversary of the 9/11 attacks.
The announcement was made on an Islamist website, where al-Qaeda's media arm frequently posts messages.
US homeland security officials could not confirm the existence of a tape, and said there was "no credible information of an imminent threat".
Al-Qaeda has put out similar statements in the past but no video has followed.
Bin Laden has not been seen in a video since October 2004, when he threatened new attacks against the US on the eve of the presidential election.
An audio tape was released in January 2006.
Dyed beard?
A banner advertisement for the video, written in Arabic, read: "Soon, God willing, a video tape from the lion sheikh Osama Bin Laden, God preserve him." Bin Laden 'to issue 9/11 video' (more)
LE FIGARO:
Ben Laden pourrait réapparaître en video
NZZ:
Al-Kaida kündigt Video mit bin Ladin an: Kurz vor Jahrestag der Anschläge vom 11. September
Mark Alexander
