The situation in Sudan has sometimes been compared to that of Rwanda 10 years ago. But is anything on that scale happening in the Darfur region of Sudan?
By Paul Welsh
BBC world affairs correspondent
The US Congress has called it genocide, and the United Nations gave the government 30 days to help the people and stop helping the Janjaweed militia, who have been blamed for the worst of the atrocities.
Ten years ago in public, the world's powers were struggling to decide whether Rwanda's massacres were genocide or war.
In reality, they already knew but did not want to get involved.
Lessons may be learnt from Rwanda's genocide to help Darfur
A few weeks into the crisis, a US defence department document marked "secret" said this: "Be careful, 'genocide' finding could commit the US government to actually do something."
Still smarting after its disastrous intervention in Somalia, America wanted to stay out of Rwanda at all costs.
"Nobody feels the blood nor the sin of it all," said General Romeo Dallaire, former commander of a small United Nations force in Rwanda. He did not have the manpower or the orders to intervene.
He sees history repeating itself in Sudan and says intervention is already late.
"No-one wants to get involved again. The... casualties [are] still there and I think the most catastrophic affair is [that] there's nobody who's giving the UN the teeth to be able to do something tangible on the ground. And that, to me, is the scandal of it all."
But have war crimes been committed?
The barrister John Jones has worked in three war crimes tribunals, including the one for Rwanda: "There's a hierarchy of crimes, genocide being the crime of crimes.
In Sudan, if you have African groups and Arab militias, you certainly have ethnic groups, and if one is trying to exterminate the other, then arguably you have genocide.
"But certainly if you don't have that then you have crimes against humanity, possibly. Crimes against humanity being widespread and systematic attacks on the civilian population."
And so, as in 1994, the legal niceties are under debate.
Hilton Dawson, chairman of the British parliament's group on Sudan, believes there is no genocide.
"I think it's wicked murder on a huge scale, but I don't believe that it's the simple targeting of one ethnic group by another. I've talked to people on the ground on all sides. There's a more complex mix of races and cultures than one would assume from simply being told that this is Arabs against Africans or vice versa."
America's Congress says there is genocide in Sudan; its state department is still investigating.
Gen Dallaire despairs: "To me, the whole exercise in calling it genocide or not is nothing more than political semantics, and so the Americans have just used - nearly flippantly - the term genocide and they've done absolutely nothing on the ground in regards to conducting an operation to stop genocide.
"The term is something that people are using as simply a statement, but no commitment to it."
Hilton Dawson says that what also has to be recognised is that this situation could be made worse.
"This is a country which has been at war for more than 20 years. We are coming to the comprehensive peace agreement which should end all fighting between north and south. It's vital that that isn't disrupted, because many more lives would be lost."
A decade ago, a secret US defence department document argued a ceasefire in Rwanda would be jeopardised by pressure to punish those organising killings.
Another memo, for the under-secretary of defence, gave this advice: "Talking points for your dinner tonight with Mr Kissinger: Is the US government willing to get involved? Not inside Rwanda or Burundi until peace is restored."
With hindsight, much has been discovered about the genocide in Rwanda and the world's response.
With time, we will know whether lessons have been learned when it came to Sudan.