UNTIL the rocks and bottles starting flying, most of the proceedings were solemn and moving, just as they were supposed to be. Celebrities from all over the world commemorated the 20th anniversary of the murder of some 8,000 Bosniak (Bosnian Muslim) men and boys by Bosnian Serb forces. Bill Clinton, the former American president and other local, foreign and Balkan dignitaries made the requisite impassioned and emotional speeches, vowing that they would never let this happen again.

Thousands listened patiently in the broiling sun. The remains of 136 victims of the Srebrenica massacre of 1995 lay waiting to join more than 6,000 others whose remains have been identified and buried in past years. Then came the prayers. So far so good: even Aleksandar Vucic, the prime minister of Serbia, had come to pay his respects and to do his bit for Balkan reconciliation. Then it all went wrong and rocks started flying.

Mr Vucic used to be an extreme nationalist who supported the Bosnian Serb leaders who committed what two international tribunals have found to be an act of genocide. Now his past is forgotten by many who see in him an advocate of modernisation and European integration for Serbia. But not by everyone.

Amongst the tombstones on the hill a giant banner was unfurled reminding everyone of something he had once said: “For one Serb, we will kill 100 Muslims.” A few minutes later Mr Vucic and others were being moved along a path between the crowds when people began to throw stones at him. A mass of angry folk began to surge forward, a chant of “Allahu Akhbar”—God is Great—went up and the security services finally began to do their job. The Serbian prime minister, who had been hit and whose glasses were broken was hurriedly evacuated.

That something of the sort would happen was entirely to be expected. The Serbian security services even warned Mr Vucic. He said he did not care. Turbulence was anticipated because, in the past few weeks, Mr Vucic and other Serbian leaders have campaigned against a British resolution condemning the events of two decades ago and their denial. What they particularly opposed was the use of the word “genocide”.

Two decades after the Srebrenica massacre, consensus about what happened is fraying On July 8th Russia obligingly stepped in to veto the resolution. On June 10th, acting on a Serbian warrant, the Swiss arrested Naser Oric, the wartime Bosniak leader of Srebrenica for alleged murders of Bosnian Serb civilians. Serbia failed in its bid to have him extradited. No wonder the mood was hostile. Whether the stoning of the prime minister will do long-term damage remains to be seen. Mile, a Srebrenica Serb taxi driver said relations in the town were always tense about this time of year “and then everything goes back to normal.” About the stoning he said: “People will talk about this for a day or two and then it will be over.” That might be true for Srebrenica, a depressing place which, this time of year apart, only has a third of its pre-war population. The consequences for the region as a whole are harder to predict. Bosniaks saw it as self-evident that the UN should pass a resolution on what happened here 20 years ago. Bosnian Serbs however say they are baffled as to why Britain chose to promote it and, in their view, stir up demons from the past. And so the status of the Srebrenica massacres has become one more quarrel along with many others which prevent Bosnia and the region as a whole from moving forward.

“The politicians are taking this country backwards,” said Dzeilana, a Srebrenica native who has settled in Sweden. Like thousands of other people from this region who now live in other parts of Bosnia or much further afield, she returns in July for a brief reunion of families and friends from a scattered, wounded community.

Sadly Dzeilana’s words are true: the unpleasant scenes which unfolded in Srebrenica today can bring no good to the town, the country or the Balkans. But Mr Vucic insisted afterwards that he would not rise to provocation. "There are fools in every nation, there is no deficit here either," he said, stressing that he "knows that a majority of Bosniaks do not agree with what happened today."