US investigators report that they have established strong financial links between al-Qaeda and the 19 hijackers. They say there is evidence showing money transfers from an account held in the United Arab Emirates by an alleged leading al-Qaeda operative, Mostafa Mohammed Ahmad, and an account in the name of Mohammed Atta, the alleged leader of the hijackers, at a bank in Florida. These are said to have taken place on 8 and 9 September 2001. Atta is also alleged to have returned unused funds to the same bank account in the UAE.

US and British forces begin air strikes against targets in Afghanistan in an attempt to overthrow the Taleban and to shut down al-Qaeda.

Osama Bin Laden warns the US that it will never enjoy security until the Palestinians also feel secure, and not until "the infidel's armies leave the land of Mohammed" - an apparent reference to US bases in the Middle East. The statement by Bin Laden is broadcast on al-Jazeera television in Qatar two hours after the US and Britain launch attacks on Afghanistan. Bin Laden does not claim responsibility for the 11 September attacks.

Former governor of Pennsylvania, Tom Ridge, takes over as director of the Office of Homeland Security. He is responsible for co-ordinating federal, state and local security activities to combat terrorism. He is responsible for gathering information on and issuing warnings on terror attacks.

The Egyptian authorities announce that they have been holding two men alleged to have connections with al-Qaeda since May. Both men are said to have had training in civil aviation.

The US widens the list of individuals and institutions whose assets it is freezing in an attempt to stop what it believes are sources of funding for terrorists. Another 37 people and groups are affected, including Saad al-Sharif, related by marriage to Bin Laden, and several Islamic charities.

The German authorities issue an arrest warrant for Zakariya Essabar, a Moroccan student alleged to have lived with three of the 11 September hijackers in Hamburg, and who worshipped at the same mosque as Mohammed Atta.

A Muslim cleric, who lives in London, denies having any links to international terrorism after his assets are frozen and his passport confiscated by the British authorities. An investigation into his alleged terrorist links revealed that Abu Qatada had more than $270,000 in his bank account. He is alleged by US and Spanish investigators to be Bin Laden�s ambassador in Europe and faces a death sentence in Jordan. Abu Qatada disappears in mid-December. He was found and arrested in October 2002.

US Congress approves anti-terrorism legislation that gives law enforcement agencies sweeping new powers to monitor and detain suspected terrorists. The bill comes in for heavy criticism from civil liberties groups.

On the same day a 55-year-old Pakistani man detained by the FBI as part of its investigation is found dead in his cell. Officials say he died of a heart attack.

More than 900 people across the US are detained without charge or trial.