Don't watch it John Travolta has the worst accent for a Serbian I have ever heard. Sounded like a retarded Russian. The movie kinda sucked for 2 high profile actors.
Saw Killing Season a twice and enjoyed it, mostly because I was there during that period (Zagreb/Sarajevo/Belgrade) and the reflection of that part of the world at that time was VERY accurate. John Travolta easily gets the award for absolute worst accent though and his acting and accent was so bad it was distracting.