- Video report by ITV News Correspondent Angus Walker
Relatives of those killed in the massacres led by Ratko Mladic have said their pain is as fresh as ever as the Serb General faces a verdict in his war crimes trial tomorrow.
Mladic is expected to be found guilty of genocide when the International Criminal Court in the Hague announces its decision tomorrow.
The bodies of some of the hundred thousands victims killed in his campaign are still being identified, including the many who were slaughtered and dumped in mass graves in the Srebrenica massacre.
A guilty verdict will help thousands find some peace. But the wounds from the war in Bosnia will take many more years to heal.
Foreign Secretary Philip Hammond has condemned the actions of a "few individuals" who targeted the Serbian leader at an event to mark the 20th anniversary of the Srebrenica massacre.
Aleksandar Vucic was forced to flee as people pelted him with water bottles, stones and other missiles.
Hammond said: "I deplore the way a few individuals have sought to ruin the solemnity of today's commemoration.
"Their action should not be allowed to detract from the sentiments felt by a majority; that the countries and peoples of the western Balkans need to move forward together in reconciliation and co-operation."
The 1995 massacre of 8,000 Muslims by Bosnian Serb forces was the worst since the Holocaust.
Serbia's interior minister has condemned what he described as a "scandalous attack" on the country's prime minister after he was chased from a Srebrenica ceremony.
Aleksandar Vucic left the event after he was targeted by angry crowds throwing stones and bottles.
"This is a scandalous attack and I can say it can be seen as an assassination attempt," Nebojsa Stefanovic said on Serbian Pink television.
"Bosnia has failed to create even the minimal conditions for the safety of the prime minister", he added.
Serbian Prime Minister Aleksandar Vucic was forced to leave an event to mark the 20th anniversary of the Srebrenica massacre today after being chased away by a crowd hurling stones and bottles.