Maritime embargo operations in support of economic sanctions have been called by some traditional or limited MIO. AS stated above, the reaction to 9/11 expanded the use of MIO to hostilities. This subsequently introduced MIO as an instrument against the wider terrorist threat beyond Al Qaida and its supporters and beyond Afghanistan. Although the operations against terrorism are generally understood by the US Government to be based on the right of self-defence, it is not the same self-defence as was used to commence Operation Enduring Freedom. The MIO conducted in the general anti-terrorism scope were called ‘expanded MIO, abbreviated to EMIO. O'Rourke states that, ‘EMIO are authorized by the President and directed by the Secretary of Defence to intercept vessels identified to be transporting terrorists and/or terrorist-related materiel that poses an imminent threat to the United States and its allies. Allen adds that EMIO are, ‘designed to intercept targeted personnel or material that pose an imminent threat to the U.S. EMIO may involve multinational forces and may be implemented even when sanctions have not been imposed.' Together with the more strategic development of a focus on maritime security, this expansion of using MIO to a wider terrorist threat moved the international community in taking the path towards Maritime Security Operations (MSO): maritime policing of the seas with a view to enhance maritime security, what in the view of the US is mainly be threatened by terrorism.