The United States and its NATO allies invaded Afghanistan in late 2001, after the Taliban refused to extradite Osama bin Laden, leader of the al-Qaeda* terrorist group, who was suspected of masterminding the 11 September 2001 terrorist attacks in New York, Washington, DC and Pennsylvania.
As the 20th anniversary of 9/11, the deadliest terrorist attacks in US history, approaches, the Taliban maintains that the US has yet to offer the group proof that Osama bin Laden was involved in or responsible for the acts of terror.