The conflict in Sudan's Darfur region has raised a disturbing question for governments and human rights activists around the world: Should the killing there be classified as genocide, and what should the world community do about it?

The war in Sudan's western Darfur region has been raging since early last year, when two rebel groups took up arms against the Arab-run government in Khartoum, demanding better treatment for the region's predominantly black population.

In response, a pro-government Arab militia, called the Janjaweed, has carried out a scorched-earth campaign that the United Nations says has killed an estimated 50,000 blacks, and driven more than a million others from their homes.

Human rights observers and refugees say Sudan's military gives support to the Janjaweed, a charge the government denies.

The United Nations calls the conflict the world's worst humanitarian crisis, and some human rights activists say it is time to invoke the 1948 U.N. Convention on Genocide to stop it.

The convention defines genocide as an attempt to intentionally destroy, in full, or in part, an ethnic or racial group, and it obliges signatory countries to prevent and punish genocide when it occurs.

The Geneva-based International Commission of Jurists has been closely monitoring events in Sudan. The ICJ's secretary general, Nicolas Howen, says Khartoum appears to be in violation of international law, whether it's called genocide or not.

"It's clear that there are mass killings, and that the government of Sudan is responsible, either through its own forces, or by supporting the Janjaweed militia," Mr. Howen says. "The next question is whether they are crimes against humanity. What's a crime against humanity? It's an international crime, where there is a systematic or widespread attack on a civilian population, which is a government policy. Is this an attempt by the government of Sudan to actually wipe out an ethnic group within the country? It may or may not be, but even if it's not genocide, it may well be a crime against humanity. It's an international crime and similar consequences follow."

A European Union investigation has concluded the killing in Darfur does not constitute genocide. U.S. government officials have carefully avoided using the word.

But a senior American lawmaker, Senate Majority Leader Bill Frist, says it is genocide, and the world community should support an African-led intervention, if a political settlement is not reached soon.

"If the official designation of genocide is made, then the international community has a very definite obligation and responsibility to take appropriate action," Senator Frist says. "I would argue that that would be acceleration of the political activity. If that is not sufficient, then, in a short period of time, meaning days to weeks because of the ongoing tragedy, people are dying every day, that then we should have a protective force composed of Africans."

The International Jurists chief, Nicolas Howen, says there is another step governments can take to bring the perpetrators of Darfur's crimes to justice, without sending in the troops.

"Every single state has certainly the ability, and even the responsibility, to act, if someone responsible for crimes against humanity lands at their airport," Mr. Howen says. "So, if it is shown that this sort of crime against humanity is happening in Sudan, then, if some of the leaders or others responsible land at an airport, then we would call on the government of that country to arrest this person, to prosecute them, or to send them to a country that will."

Mr. Howen says the U.N. Security Council could pass a resolution referring the Darfur matter to the International Criminal Court, which could then determine if individuals should be tried.

And, he says, the question of whether genocide is occurring should not prevent governments from taking action.

"What I don't want is to have a semantic argument about definitions," Mr. Howen says. "Genocide has a particular definition in international law, but let's not argue about whether it is genocide or not. It's clear there are mass killings, which are taking place. Surely, 10 years after Rwanda, mass killings demand an urgent and immediate response."

For the time being, the world community is waiting to see if Khartoum complies with a Security Council resolution that gives Sudan until the end of this month to disarm the Janjaweed. The resolution calls for as yet unspecified sanctions, if Sudan does not comply.