The terrorists responsible for the September 11, 2001 attacks were 19 men affiliated with the Islamist extremist group al-Qaeda. These hijackers came from four countries: 15 were citizens of Saudi Arabia, two from the United Arab Emirates, one from Egypt, and one from Lebanon. They hijacked four commercial airplanes, crashing two into the North and South Towers of the World Trade Center in New York City, one into the Pentagon in Arlington, Virginia, and the fourth into a field in Pennsylvania after passengers attempted to regain control

. The ringleader of the hijackers was Mohamed Atta, an Egyptian national, who led the team on American Airlines Flight 11 targeting the North Tower. Other hijacker-pilots included Marwan al-Shehhi (UAE), Ziad Jarrah (Lebanon), and Hani Hanjour (Saudi Arabia). The hijackers were organized into four teams, each assigned to a specific flight and target

. The U.S. government and intelligence agencies quickly identified Osama bin Laden and al-Qaeda as responsible for orchestrating the attacks. Bin Laden and senior al-Qaeda members claimed responsibility in various statements. The FBI's investigation, the largest in its history, confirmed the hijackers' identities and their ties to al-Qaeda

. In summary, the 9/11 terrorists were 19 al-Qaeda operatives primarily from Saudi Arabia and nearby countries, led by Mohamed Atta, who carried out coordinated hijackings and suicide attacks on major U.S. landmarks