On 12 September 2001 NATO implemented Article 5 of the Washington Treaty
following the 11 September attacks against the United States. Following US
requests, NATO subsequently agreed to implement 8 specific measures to
expand the options available in the campaign against terrorism. These
measures included the deployment of elements of NATO’s Standing Naval
Forces to the Eastern Mediterranean in order to provide a NATO presence
and demonstrate resolve. The NATO Operation ACTIVE ENDEAVOUR formally
began on 26 October 2001, when the activation order was issued. However,
patrolling in the Eastern Mediterranean had already started on 6 October,
when the Standing Naval Force Mediterranean was dispatched to conduct
maritime presence operations in support of the international campaign
against terrorism.