Dictator Tito held the separate entities of Yugoslavia together ...  vying for autonomy, the entities had to settle differences from the 2nd World War. Why not build up your army so to settle territorial claims in your favor.

Croatia and Nazi Germany

Serbs supported by Russia

Bosnia Herzegovina supported by Islamic states and Turkey

Once again the US opened a arms supply line with support from Turkey, Saudi Arabia and Qatar. All parties had agreed to a UN arms embargo .... it failed.

Read the volumes on the Fall of Srebrenica and the Dutch Blue helmets.

Croatian arms pipeline

Night flights of cargo planes fully loaded with arms and munition landed in Tuzla in UN Safe area protected by the Dutch. Flights also transported jihadists and thus a first Al Qaeda base was created inside Europe. During the night Muslim Bosniak militia would use guerrilla tactics to ambush the Serbs. The Dutch military were aware that the Bosnian operatives made their operation more difficult.

Hasbara is a dead language