ISLAMABAD - Assistant US Secretary of Defence for Special Operations, Low Intensity Conflict, Michael Vickers along with Admiral Eric T Olson, Commander, Special Operation Command called on Chief of Army Staff (COAS) General Ashfaq Parvez Kayani at GHQ on Tuesday. According to ISPR, the visiting dignitaries remained with COAS for sometime and discussed the matters of professional interest. Meanwhile, Ambassador Michael Steiner, Special Representative of German Federal Government for Afghanistan and Pakistan also called on Chief of Army Staff and discussed matters of mutual interest.