On 12 September, a day after the terrorist attacks in the United States of America, NATO invoked the principle of Article 5 of the Washington Treaty. After confirming that such actions had been conducted from abroad the Article became fully operative on October 2, 2001.
Operation APOLLO was Canada's military contribution to the international campaign against terrorism from October 2001 to October 2003.
The Canadian Forces' Contribution
to the International Campaign Against Terrorism
[ January 01, 2004]