On September 16, migrants prevented by the new fence by crossing the border near Horgoš, Serbia, and Röszke, Hungary, reacted by surging forward and pushing or tearing away a section of the new fence. Hungarian riot police responded with tear gas, causing the migrants to fall back, then regroup and surge forward again, only to be met by another round of tear gas canisters and with water cannon. At this point some of the migrants began tearing apart a decayed structure, to obtain chunks of concrete which, along with rocks were hurled at police as other rioters built debris fires, filling the air with smoke. The riot subsided as word spread the Hungarian police had opened a nearby gate, but as 200 or 300 migrants walked through the newly opened gate, Hungarian police "surged forward", swinging batons and firing tear gas into the crowd of migrants.[17][18]

Hungary was widely criticized for its use of tear gas and water cannon against migrants attempting to enter the country.[19] Hungary commented the border security: "the official and legal ways to come to Hungary and therefore to the European Union remain open. That's all we ask from all migrants - that they should comply with international and European law."[20]