Genocide survivors have urged the European Union to do far more to help end the violence in the western Sudanese region of Darfur.
Some two million people were turned refugees
The call was contained in an open letter, signed by 120 survivors of the Holocaust, and the genocides in Cambodia, Rwanda and Bosnia.
Their message was backed by six leading aid agencies, calling on the EU to increase pressure on Sudan.
EU leaders later said a UN peacekeeping force was "the only viable option".
But the Sudan government is refusing to let such a force into Darfur.
At the moment, 7,000 African Union troops are deployed in the conflict-torn region, but they are said to be undermanned and ill-equipped for the job.
They have been unable to end the violence, which has led to about two million people fleeing their homes since 2003.
Studies estimate at least 200,000 people have died during the conflict, in which pro-government Arab militias are accused of committing a genocide against Darfur's black African population.
Sudan says the problems have been exaggerated for political reasons.
"The African Union has worked very well in Darfur and done what it could," James Smith, director of the British-based Aegis Trust, told the BBC's World Today programme.
"But the rest of the world hasn't supported those efforts the way it should have done with sufficient funds and sufficient equipment," he added.
The Aegis Trust has helped organise the genocide survivors' open letter, calling for action by the EU leaders gathered for a summit in Finland.
Meanwhile, a conference is being organised in London, bringing together survivors from genocides throughout the past 60 years, Mr Smith told the BBC.
"From the Holocaust in Europe, when six million Jews were killed by the Nazis, to survivors from Bosnia, from Rwanda, from the genocide in Cambodia, and, indeed, survivors from Darfur itself," Mr Smith said.
The survivors insist that the EU leaders step up pressure against the Sudanese government, accusing them of being "bystanders" to the mass killing in Darfur.