They fear the site is embedded with secret codes and instructions of use to militants including affiliates of Osama bin Laden's Al-Qaeda network, Newsweek has reported.

Azzam.com, an entity operated by an unknown group of individuals under the auspices of Azzam Publications, is named for Abdullah Azzam, a Palestinian militant killed in a 1989 bomb attack in Pakistan.

It has no bricks and mortar address, but operates a post office box in London, and bills itself as "an independent media organisation providing authentic news and information about jihad and the Foreign Mujahideen everywhere".

In an open letter to US President George W. Bush and throughout the website, Azzam Publications is virulently anti-American and anti-Western, openly recruiting martyrs for a global jihad and disputing Muslim involvement in the September 11 attacks on the US.

A recent posting, dated December 9, is datelined from the southern Afghan city of Kandahar and is a message to Muslim youth from top terror suspect Osama bin Laden.

The message underscores reported US suspicion that supporters of the Saudi-born multimillionaire, whom Washington blames for the attacks on New York and the Pentagon, are behind the Internet site.

A farewell message from Azzam Publications dated November 20, still on the website, exhorts "Muslims all over the World (to) render as much financial, physical, medical, media and moral support to the Taliban as they can".

Newsweek reported that European hackers who broke into its German-based subscriber list found an e-mail address for Said Bahaji, a fugitive identified as a member of the September 11 hijacking cell based in Hamburg, northern Germany.

The magazine has reported in its issue out tomorrow, the belief of British and US intelligence sources that some of Azzam.com's jihad photos and graphics contain messages embedded with a technology known as steganography – so sophisticated it is difficult for intelligence agencies to decode.

Agence France-Presse