 Bulgaria hosted six KC @-@ 135 Stratotanker aircraft and 200 support personnel for the war effort in Afghanistan in 2001 , which was the first stationing of foreign forces on its territory since World War II . International military relations were further expanded in April 2006 , when Bulgaria and the United States signed a defence cooperation agreement providing for the usage of <unk> and Graf <unk> air bases , the Novo Selo training range , and a logistics centre in <unk> as joint military training facilities . The same year Foreign Policy magazine listed <unk> Air Base as one of the six most important overseas facilities used by the USAF due to its proximity to the Middle East . A total of 756 troops are deployed abroad as part of various UN and NATO missions . Historically , Bulgaria deployed significant numbers of military and civilian advisors in Soviet @-@ allied countries , such as Nicaragua and Libya ( more than 9 @,@ 000 personnel ) . 
