On the theory that the Army of the Republic of Bosnia and Herzegovina possesses a superiorly motivated and effective infantry , it was deemed that the `` Bosnian Serb '' Army was reliant on its overwhelming firepower and the siege of civilian areas in order to retain its overall military advantage . Before the creation of the North Atlantic Treaty Organization ( NATO ) -implemented `` exclusion zone '' around Sarajevo in February 1994 , UNPROFOR not only avoided measures that might risk reducing the Bosnian Serbs ' firepower advantage , but also acquiesced in the ongoing siege of Sarajevo . ( This Permanent Representative was told on more than one occasion by UNPROFOR functionaries that Bosnian Serb tightening of the siege of Sarajevo and even shelling of civilian areas of Sarajevo must be understood as a countermeasure to pressure undertaken by the superior Bosnian Army infantry in some other battle area within the Sarajevo area or beyond . )