The Prime Minister of Serbia was chased by angry memorial visitors during a ceremony for victims of the 1995 Srebrenica massacre in Bosnia. World dignitaries and thousands of others gathered in Bosnia-Herzegovina to remember the victims. Outrage erupted at the solemn event attended by thousands as Serbian Prime Minister Aleksandar Vucic walked to the Srebrenica graveyard where other politicians were paying their respects.

It has been 20 years since the Bosnian Serb army killed 7,000 Muslim men and boys at Srebrenica. For three days starting on July 11, 1995, ethnic Serb forces gunned down Muslim boys and men in and around Srebrenica in an ethnic cleansing effort. Their bodies were dumped into a mass grave. The slaughter of civilians toward the end of the Bosnian war eventually claimed around 100,000 Muslim lives, including children, women and old men. The event has been called the largest single atrocity in Europe since World War II.

People hissed and yelled as Vucic walked to the site, angered by the appearance of an official from a country that once directed the Bosnian Serbs militants. Members of the shouting crowd then began to throw bottles and rocks at him, forcing him to flee the event. As the crowd got louder and more angry, his dark-suited security staff rushed him up the graveyard’s hill and ushered him into his car. A driver hurriedly spirited him away as the objects continued to fly.

Vucic reported that he was hit in the mouth by a stone, but other than that, he was okay. He said to reporters in Belgrade, “I regret that some people haven’t recognized my sincere intention to build friendship between Serbian and Bosniak people.” He continued, “I still give my hand to the Bosniak people. I will continue with that … and always be ready to work together to overcome problems.”

The U.S. Embassy in Bosnia-Herzegovina released a statement on the matter that said, “Many of the mourners were horrified by the violence and disheartened that it disrupted the solemnity of the anniversary. The U.S. Embassy in Sarajevo shares that sentiment, and urges all to focus once again on the victims of the Srebrenica genocide and their families.” Russia, a Serbia ally, recently vetoed a U.N. Security Council measure that would have labeled the massacre as genocide, inflaming tensions in the region.