The British intelligence service has launched an Internet investigation to appeal for information about potential terrorist attacks. An Arabic message has been posted in the discussion forums of several Muslim extremist Web sites, in the hope that fundamentalist groups who were shocked by the attacks on the World Trade Center and the Pentagon last month will approach MI5 with new terrorist information. "We want people to give information that could prevent further terrorist atrocities -- it is to remind those who might have information about 11 September that they can speak in confidence to the security services, to prevent further attacks," said a Home Office spokesman. Sources who have worked with the security service in the past say that if MI5 is involved in such an operation, it would also be gaining intelligence by getting officers to pose as terrorists in extremist discussion forums. The appeal message has been posted on a Saudi opposition site www.islah.org and a Chechen pro-jihad site www.qoqaz.com. The Home Office has confirmed that other dissident Arab Web sites have also been targeted, but is refusing to name them. "The atrocities that took place in the USA on 11 September led to the deaths of about five thousand people, including a large number of Muslims and peoples of other faiths," reads the message. "MI5 (the British security service) is responsible for countering terrorism to protect all UK citizens of whatever faith or ethnic group. If you think you can help us to prevent future outrages call us in confidence on 020 7930 9000." MI5 officers will be responding to calls received on the public telephone number, which has been in existence since March 1998. The Home Office has not yet analysed the responses received, but The Guardian reports that the Islah Web site received 700 hits within 24 hours, and attracted 16 malicious responses. See the Internet News Section for full coverage. Have your say instantly, and see what others have said. Click on the TalkBack button and go to the Telecoms forum. Let the editors know what you think in the Mailroom. And read other letters.