Vucic's security detail rushed him away, trying to protect him with bags, umbrellas and their raised arms from the projectiles raining down. His guards rushed him through the angry crowd before pushing him inside an armored vehicle.
"We were attacked from all sides. It was well organized and prepared," a visibly shaken Vucic said upon his quick return to Serbia. He blamed hooligan soccer groups from Serbia and Bosnia for initiating the attack.
"Except for my glasses, I'm missing nothing else," he said.
But Vucic, who came to represent Serbia at the commemoration in an apparent gesture of reconciliation, said after the attack that, "Today we are talking more about a bunch of fools rather than about the innocent victims of Srebrenica. He added that his "arms of reconciliation remain stretched toward the Bosniaks."
The Muslim Bosniak mayor of Srebrenica, Camil Durakovic, apologized to Vucic, saying he was "deeply disappointed" about the attack.
Tens of thousands of people came to the commemorations marking two decades since Europe's worst massacre since the Holocaust.
Foreign dignitaries urged the international community not to allow such atrocities to happen again and to call the crime a "genocide." Serbia and Bosnian Serbs deny the killings were genocide, and claim that the death toll has been exaggerated.
"I grieve that it took us so long to unify ... to stop this violence," said former U.S. President Bill Clinton, who was in office at the time of the massacre and whose administration led the NATO airstrikes against Serb positions. This ended the Bosnian war and the United States brokered a peace agreement.
Clinton said before the attack on Vucic: "I want to thank the prime minister of Serbia for having the courage to come here today and I think it is important that we acknowledge that."
Council of Europe Secretary General Thorbjorn Jagland condemned the attack. The ceremony in Potocari, the Srebrenica suburb where the memorial center is located, "should have been a place for reflection, reconciliation, not violence," Jagland said.
It wasn't the first time that top Serbian officials visited Srebrenica for commemorations. The former pro-democratic president, Boris Tadic, was there twice, including on the 10th anniversary of the massacre, and there were no major incidents.
In what has become annual ritual as more graves are discovered, the bones of newly identified victims will be interred beneath marble gravestones in the Potocari memorial cemetery.
"One cannot describe with words how I feel today," said Zijada Hajdarevic as she escorted the remains of her brother on Thursday from the morgue to the cemetery, where her grandfather and other close relatives are all buried.
"We knew he was gone, but it will be easier now we know where we can visit his grave," said Hajdarevic, who is still searching for her father.
During the war, the U.N. declared Srebrenica a safe haven for civilians. But on July 11, 1995, Serb troops overran the Muslim enclave. Some 15,000 men tried to flee through the woods toward government-held territory while others joined the town's women and children in seeking refuge at the base of the Dutch U.N. troops.
The outnumbered Dutch troops could only watch as Serb soldiers rounded up about 2,000 men for killing and later hunted down and killed another 6,000 men in the woods.
The U.N. admitted its failure to protect the town's people and on Saturday, Bert Koenders, foreign minister of Netherland said that "the Dutch government shares responsibility" and that the U.N. must strengthen its missions in the future.
"Nobody can undo what happened here but we mourn with you," Koenders added.
The 1992-95 war in Bosnia, pitting Christian Orthodox Serbs against Bosnian Muslims and Croatian Catholics, left more than 100,000 people dead and millions homeless. The Serbs, who wanted to remain in the Serb-led Yugoslavia, fought against the secession of Bosnia and Croatia from the former federation.
Many Serbs dispute the death toll and the official account of what went on — reflecting conflicting narratives of the Yugoslav wars that still feed political divisions and stifle progress toward integration with Western Europe.
Bosnian Serb leader Milorad Dodik last month described Srebrenica as "the greatest deception of the 20th century."
So far, remains of some 7,000 victims have been excavated from 93 graves or collected from 314 surface locations and identified through DNA technology.
Al Jazeera and wire services