Leading article: We must not betray this blighted part of Africa

The Darfur peace deal signed four months ago is on the verge of collapse. The African Union has called for the United Nations to take over its peacekeeping mandate in the region that is due to expire at the end of the month. But the Sudanese government refuses to accept this. Khartoum is now demanding the withdrawal of the AU's 7,000 troops by the end of September and has warned of a "confrontation" if the UN attempts to deploy its own peacekeepers.

Meanwhile, the Sudanese government has sent thousands of its troops to the region and last week launched attacks on rebel positions, in what appears to be another attempt to end the conflict by superior force of arms. A return to full-scale hostilities is a real possibility.

The situation in Sudan is far from clear cut. The conflict in Darfur is often described as a clash between ethnic African tribes and the Arab-led government and its local janjaweed militia. But this fails to take into account that one of the Darfur rebel groups has joined forces with Khartoum. The ethnic lines of the struggle have been blurred. An agreement that involves all the rebel groupings will be necessary to deliver a lasting settlement. It is not a simple question of the outside world putting pressure on Khartoum.

Matters are also complicated by the fact that the international community is eager not to upset the fragile UN-brokered peace agreement signed by the Sudanese government with another set of rebels in the south of the country three years ago, after half a century of conflict. This explains why the international community has tried to avoid confrontation with the regime in Khartoum.

Yet that peace deal has led to instability elsewhere in the country. The rebellion in Darfur in 2003 seems to have sprung from a belief by local leaders that they were not receiving a fair share of income from Sudan's natural resources. They saw what they thought was an opportunity to push for parity. Nor were they alone. The Sudanese government is facing new insurgencies in the east and the north of the country too. This combination of political separatism, ethnic animosities and competition for resources make the situation in Sudan as intractable as parts of the Balkans. Simplistic attempts to portray the regime in Khartoum as a collection of Islamist fanatics are dangerously misleading.

But one thing is perfectly clear cut: the scale of the humanitarian disaster afflicting the civilians of Darfur. Since 2003 more than 200,000 have died because of government forces and the janjaweed. More than two million have been displaced and are living in camps that are desperately short of food, water and medicine. This is a humanitarian crisis more urgent than even those in Lebanon and Gaza.

But there is still a way out. Under the terms of the peace deal struck in May, Khartoum promised to disarm the janjaweed. But there has been no evidence of this. Indeed, the Sudanese government continues to use the militia as a proxy army. This clear breach of faith by Khartoum means there is more scope for the UN to bring diplomatic pressure on Sudan. It also means there are grounds for hope that China, Sudan's major oil client and supporter on the Security Council, can be persuaded to acquiesce to sanctions on Khartoum unless UN peacekeepers are given access to Darfur.

The deployment of such a force would be no political panacea for Sudan and its panoply of crises. But it would at least afford a minimum degree of protection for the displaced and suffering of Darfur. Until such an agreement is in place, any attempt by the international community to turn its back on this part of Africa would represent a grotesque betrayal.