Some 40,000 people converged on the Bosnian town of Srebrenica Sunday, to mark the 15th anniversary of the 1995 massacre in which Serb forces captured the town and began executing Muslim boys and men, according to dpa. Braving the stifling heat, they paid their last respects to another 775 identified victims - 774 Muslims and one Croat - at the Potocari memorial centre who were laid to rest along with more that 4,500 who were already buried there. Serb forces executed around 8,000 men and boys days after they rolled into Srebrenica on July 1, 1995, four months before the 1992-95 Bosnian war ended. Srebrenica had been declared a safe haven for Muslims and was under the protection of United Nations. In a personal message, US President Barack Obama said that people massacred at Srebrenica had put their faith in the fact that the international community would protect them and said that justice meant "complete responsibility." The Bosnian Serb general "Ratko Mladic, who led the executions, is still free - we must not let the crime of such proportions remain unpunished," said Obama in a letter read by the US Ambassador Charles English. Many politicians from the region and beyond joined the mourners in Potocari, including the Belgian Prime Minister Yves Leterme, whose country currently holds the rotating presidency of the European Union. "All those who took part in the killings must be punished," French Foreign Minister Bernard Kouchner said. Turkish President Recep Tayyip Erdogan said "around 10,000 innocent people were killed in the surrounding hills in a classical act of ethnic cleansing." The international community's high representative in Bosnia, Valentin Inzko, blasted the Bosnian Serb leadership over recent statements insisting that the number of the killed in Srebrenica was overblown and that no genocide had occurred there. "Those who bring into question the genocide at Srebrenica have no future and are not a part of our civilization," he said. The massacre in Srebrenica began shortly after Serb forces, under Mladic's command, brushed aside 850 UN peacekeepers from the Netherlands who were protecting the enclave and took control of the town. SPA