The terrorist attacks of September 11, 2001, on New York's World Trade Center Towers and Washington's Pentagon, instantly refocused the United Nations' attention on the issue of international terrorism. The Security Council (Council) responded immediately: first, on September 12, 2001, with an unequivocal condemnation of the attacks, contained in Resolution 1368 (2001), and second, on September 28, 2001, with the enactment of Resolution 1373 (2001), which, under Chapter VII of the Charter, mandated that all Member States take specific actions to combat international terrorism. Terrorism was rightly understood to be "a threat to international peace and security."
Emilio J. Cárdenas,
The United Nations Security Council's Quest for Effectiveness,
Mich. J. Int'l L.
Available at: https://repository.law.umich.edu/mjil/vol25/iss4/29