▁of ▁military ▁equipment ▁and ▁training , ▁as ▁well ▁as ▁the ▁absence ▁of ▁a ▁friendly ▁ad jo ining ▁country ▁offering ▁san ctu ary . ▁ ▁There ▁have ▁been ▁two ▁liber ation ▁movements ▁against ▁an ▁African ▁power ▁over ▁the ▁borders ▁drawn ▁during ▁the ▁colonial ▁period . ▁The ▁Pol is ario ▁Front ▁began ▁a ▁struggle ▁in ▁ 1 9 7 3 ▁for ▁the ▁independence ▁of ▁Western ▁Sah ara ▁against ▁Spain ▁and ▁then ▁Mor oc co , ▁when ▁the ▁North ▁African ▁country ▁inv aded . ▁ ▁In ▁E rit rea , ▁the ▁E rit re an ▁Liber ation ▁Front ▁and ▁later ▁E rit re an ▁People ' s ▁Liber ation ▁Front ▁carried ▁out ▁an ▁independence ▁struggle ▁against ▁Eth iop ia ▁that ▁cul min ated ▁successfully ▁in ▁ 1 9 9 1 . ▁ ▁In ▁two ▁special ▁cases , ▁and ▁in ▁contrast ▁to ▁these ▁blo ody ▁wars , ▁both ▁Nam ib ia ' s ▁South - West ▁Africa ▁People ' s ▁Organisation ▁( 1 9 6 0 s – 1 9 9 0 ) ▁and ▁the ▁activities ▁of ▁Um kh onto ▁we ▁S iz we , ▁the ▁military ▁wing ▁of ▁South ▁Africa ' s ▁African ▁National ▁Congress , ▁util ized ▁armed ▁conflict ▁compar atively ▁less ▁in ▁their ▁strugg les . ▁ ▁Post - colon ial ▁ ▁African ▁states ▁have ▁made ▁great ▁efforts ▁to ▁respect ▁inter state ▁borders ▁as ▁in vi olate ▁for ▁a ▁long ▁time . ▁For ▁example , ▁the ▁Organ ization ▁of ▁African ▁Unity ▁( O AU ), ▁which ▁was ▁established ▁in ▁ 1 9 6 3