As the genocide in Darfur goes on, chaos and killing spread to Sudan's neighbours

It has been called a genocide in slow motion, its gruesome details unfolding while the world looks the other way. And it is spreading.

There are pictures, there are witness accounts, there are the Western visitors who go home with harrowing tales of rape, scorched earth and horseback attacks on helpless villagers.

Yet, three years after the beginning of the Sudanese government crackdown against black African rebels, killing more than 70,000 people and displacing two million others through its allied Arab militias, the world is still wringing its hands while Sudan's western region burns.

A UN force for Darfur is still in the planning stages, an attempt to punish Sudanese leaders with sanctions has been blocked, and relief agencies have been denied access to 300,000 people desperately in need of emergency supplies.

"It's a big failure for the international community," said the UN high commissioner for refugees, António Guterres. But the poison from Darfur threatens to engulf the entire central African region.

Chadian rebel attempts to overthrow President Idriss Déby in lightning strikes launched from across the border in Darfur last week have brought accusations that the Sudanese government was behind the insurgency. Chinese-made equipment - China is a major oil client of Khartoum and its diplomatic ally - seized by the Chadian army fuelled the charges which Khartoum has denied.

According to Mr Guterres, the Chad fighting, which also involved the Central African Republic, means that "Darfur is the epicentre of what could be potentially a very damaging earthquake in the whole region." A total 200,000 Sudanese refugees have fled to camps in Chad.

Rebels of the Lord's Resistance Army, based in northern Uganda, send fighters into Central African Republic, and into Democratic Republic of Congo and are complicating efforts to return refugees into southern Sudan, according to Mr Guterres. The regional crisis could further worsen if Ethiopia and Eritrea rekindle their border war.

"I do believe this has the potential to become the most dramatic humanitarian catastrophe in the world," Mr Guterres told The Independent.

The chief UN humanitarian co-ordinator, Jan Egeland, was expected to inform the UN Security Council yesterday that the Darfur crisis had reached a turning point. While a few months ago the violence had seemed to be abating as the Sudanese responded to international pressure, the tide is now turning again with atrocities on the rise, people being forced from their villages by marauding militias and relief workers given ever shrinking access to the local people.

Since last summer, Mr Guterres said, "the international community was not active enough, and the African Union was left a bit alone, and now the situation has become unbearable".

In the past few months, Sudan has played for time while it drove a wedge between the veto-holding powers on the UN Security Council, and while under-resourced African Union "ceasefire monitors" struggled to carry out their mandate in Darfur.

On Monday, Russia and China, which both have economic interests in Sudan, blocked the imposition of a US and UK-backed travel ban and assets-freeze against four Sudanese leaders. Their veto prompted the US to force a public vote on the issue later. The two countries argued that sanctions would send the wrong message at a time when a new deadline of 30 April has been set by UN envoy Salim Ahmed Salim for securing a comprehensive ceasefire between the Sudanese government and Darfur rebel groups.

Sudanese government leaders used the same argument to bar a UN team from travelling to Darfur this week in order to assess prospects to transfer peace-keeping in the region from the African Union to the UN later this year. Sudan says that UN peacekeepers should only move in to monitor a peace settlement.

But analysts argue that external pressure on the Sudanese government had to be an essential part of the UN arsenal. "This is a vicious regime. Without external pressure, nothing will happen," said one African analyst. "We're not talking about a nice government, one that cares about its people."

A former member of the African Union mediating team, a South African, Laurie Nathan, believes that the repeated deadlines set by the international community, which systematically slide, are pointless.

"This deadline diplomacy adds an element of farce to the deadly conflict raging in Darfur. It is intended to constitute pressure on the belligerent parties and convey the international community's seriousness about resolving the conflict," he said. "But since the deadlines come and go without any negative repercussions for the parties, they are not an effective form of pressure and they undermine the seriousness of the international community."

Mr Nathan believes that for both the government and the rebel groups, whose factions are now fighting each other in Darfur, "the battlefield remains the strategic area of struggle."

Although the mediator, Mr Salim, was reported to be upbeat earlier in the week when he briefed the Security Council on his efforts, he has told colleagues he has never come across parties so unwilling to negotiate with each other as in the Darfur negotiations.

With the Darfur conflict now pushing into Chad - raising fears that the chronically unstable country might go the same way as Somalia - prospects for UN action have been further complicated. "It's very worrying," said one UN diplomat.

The spreading ethnic conflict that, broadly speaking, pits black Africans against Arab fighters - has also raised fears of a broader war in an oil-rich region that could mirror the civil war in Democratic Republic of Congo where big powers were in the background on opposing sides.

In the case of Darfur, the lines are now drawn with China and Russia firmly on the side of Khartoum.

But even Britain and the US, which have consistently taken a hard line against the Sudanese government, are wary of destabilising a regime whose support is needed in the "war on terror". The fifth UN security council member, France, meanwhile, remains the power broker in Chad.