GENEVA - The top United Nations human rights official said the situation in Syria was reminiscent of Bosnia's sectarian war and called on world powers on Thursday to unite in trying to halt the bloodshed."The memories of what happened in Bosnia and Herzegovina should be sufficiently fresh to warn us all of the danger of allowing Syria to descend into an all-out sectarian conflict," UN High Commissioner for Human Rights Navi Pillay said."It should not take something as drastic as Srebrenica to shake the world into taking serious action to stop this type of conflict," she told reporters. The July 1995 massacre in Srebrenica was the worst on European soil since World War Two. Dutch UN peacekeepers abandoned what had been designated a UN safe haven to advancing Bosnian Serb forces who then killed 8,000 Muslim men and boys and bulldozed their corpses into pits.Pillay, a former UN war crimes judge, said both sides in the Syrian conflict may have committed war crimes or crimes against humanity."The indiscriminate use of heavy weaponry by government forces to destroy large swathes of cities such as Homs and Aleppo is inexcusable, as is the use of huge bombs by extremist opposition groups which kill and maim civilians as well as military targets," she added.