The British government issues a statement saying it is confident that Osama bin Laden and the al-Qaeda network "planned and carried out the atrocities of 11 September," and setting out the evidence for their conclusion.

Afghanistan, October 1, 2001 © Teun Voeten US military forces launch ‘Operation Enduring Freedom’ against Taliban and al-Qaeda facilities in Afghanistan. In a televised address, President Bush says US actions "are designed to disrupt the use of Afghanistan as a terrorist base of operations, and to attack the military capability of the Taliban regime."

President Bush signs the USA Patriot Act into law. The act gives the Attorney General the power to detain foreigners if he has "reasonable grounds to believe" that they are engaged in an activity that endangers the national security of the United States, so long as they are charged or released within seven days. It also allows him to deport or refuse entry into the country to anyone who supports or raises money for a terrorist group.

The Department of Justice issues an interim rule allowing prison authorities to monitor communications between inmates and their lawyers, where the Attorney General has certified that "reasonable suspicion exists" that the inmate is using these communications to further or facilitate acts of violence or terrorism.