Rape, torture, and one million forced to flee as Sudan's crisis unfolds. Will we move to stop it?

The first sign is the ominous drone of a plane. Ageing Russian Antonovs sweep over the remote Sudanese village, dispatching their deadly payload of crude barrel bombs. They explode among the straw-roofed huts, sending terrified families scurrying for safety - but there is none.

Next comes the Janjaweed, a fearsome Arab militia mounted on camels and horses, and armed with AK-47 rifles and whips. They murder the men and boys of fighting age, gang-rape the women - sometimes in front of their families - and burn the houses. The villagers' cattle are stolen, their modest possessions carted off.

Survivors dash for the border with neighbouring Chad, where hordes of Sudanese refugees are clinging to life in an inhospitable desert area, threatened by disease epidemics, looming famine and still more attacks.

This is where some of the world's worst human rights abuses are occurring and nothing is being done to stop it. This is ethnic cleansing Sudanese-style. A government-sponsored campaign, led by Arab tribesmen against their black African neighbours, has triggered the greatest humanitarian crisis of our time and - with the world's eyes fixed on Iraq - its most forgotten calamity.

According to a confidential UN human rights report, seen by The Independent, the government forces are leading a "reign of terror", perpetrated by war criminals. But, because of apparent delaying tactics by the government of Sudan, the report will not be aired at a UN Human Rights Commission meeting today.

More than one million people have been displaced since war erupted in Darfur - a remote western province the size of California - early last year. Another 110,000 people have crossed into the mine-strewn deserts of eastern Chad.

According to the International Crisis Group, Darfur represents the "potential horror story in 2004". The Overseas Development Institute says there is "a clear risk of large-scale famine mortality".

After initially refusing to allow the UN team to visit Darfur, the Sudanese authorities changed their mind at the last-minute this week - delaying the confidential report's publication until after today's vote on whether to send a UN envoy to the country.

The delay has provoked outrage from human rights campaigners, who see it as a blatant ploy to deflect scrutiny of its notoriously poor human rights record. Jemera Rone of Human Rights Watch said: "The Sudan government is trying to delay and delay these missions. It is trying everything it can to avoid UN censure."

There is much to hide. Darfur has been at war since the Sudan Liberation Army (SLA) launched a rebellion early last year, citing economic marginalisation, chronic underdevelopment and the government's failure to protect farming tribes from attacks by armed Arab nomads. The SLA was later joined by a second rebel group, the loosely-allied Justice and Equality Movement (JEM).

The war has pungent echoes of the 21-year conflict in the south of the country against SPLA rebels, which is now winding down because of peace talks in neighbouring Kenya. To quell the southern insurgency, Khartoum sent squadrons of bombers, armed local Arab militas and manipulated Western aid. Now it is using the same ruthless tactics in Darfur.

Despite sporadic fighting between government and rebels, the brunt of the war has been borne by defenceless civilians. This week's UN report echoes earlier human rights investigations into its "scorched earth" strategy targeted at the Zaghawa, Massalit and Fur tribes, which are accused of supporting the two rebel groups.

Russian cargo planes attack first, dropping crude bombs into towns and villages with wells or markets. Refugees describe the bombs - which in the southern war were simply oil drums packed with explosive and metal shards - as "big barrels". Others say they were attacked by helicopter gunships.

Those who survive the aerial bombardment are attacked in a follow-up offensive led by Janjaweed militia, regular government soldiers, or both. From nomadic Arab tribes, the Janjaweed have traditionally battled with Darfur's farming and trading tribes for control of the area's scarce resources.

The UN report said: "Janjaweed were invariably said to use horses and camels, while government soldiers were described as travelling in military vehicles. Both were dressed in combat fatigues and both were well-armed."

An orgy of destruction and bloodshed ensues. Some victims talk of being stripped and repeatedly whipped or beaten with the butt of a gun. The Janjaweed round up herds of cattle, camels and goats and steal all other possessions.

The theft of livestock - the main form of wealth in Darfur - is to render the villagers destitute for life. Some of the stolen goods are sold in government-controlled towns. More than 100 desperate refugees handed lists of their stolen goods to the UN researchers.

Sexual violence is a widely used "weapon of war" according to the UN report. Gangs of Janjaweed men rape non-Arab women, sometimes at gunpoint and in front of family members. The rape is usually accompanied by beating or whipping.

Some victims have become pregnant, although researchers admit accurate information is difficult to establish due to the intense local stigma. Some assaults have clear racial overtones. One 18-year-old woman told Human Rights Watch (HRW) that her attacker stuck a knife into her vagina, saying: "You get this because you are black."

During such attacks, hundreds of children have been abducted, according to HRW, echoing slave raids carried out by another government-sponsored Arab militia, the Murahaleen, in southern Sudan.

Human rights groups say the spectre of ethnic cleansing, driven by province-wide panic and fear, hangs over the co-ordinated government attacks. The Intermediate Technology Development Group estimates that up to 60 per cent of villages have been "destroyed, burnt or abandoned because of attacks from the warring parties."

Until last January, President Omar el-Bashir's government prevented international humanitarian assistance to Darfur. Since then, a handful of agencies have moved into the province but their movements remain severely restricted by the government.

Some have witnessed the atrocities first-hand. Ben Parker, a UN aid worker, said yesterday: "I saw a village on fire east of El Genenina on Wednesday. The people ran away when they saw our car. We felt it wasn't safe to stop. I can't say I saw the Janjaweed lighting the match but that is their modus operandi."

Exhausted, terrified and hungry, and with nowhere else to run, about 110,000 refugees have crossed into Chad. They have found scant protection in their supposed desert refuge.

Some parts are still littered with landmines and other unexploded ordnance from Chad's own civil war in the 1970s. In some camps, up to 80 per cent of the refugees are children. Their fathers are thought to be dead, to have remained behind to salvage their possessions, or to have joined the rebel forces.

Western aid agencies are struggling to provide the refugees with water, food and medicine in extremely difficult conditions. Disease is a hovering threat - in Tine town, doctors reported 25 incidences of meningitis, which is above the threshold for an epidemic. Relief workers fear a rapid deterioration of conditions over the coming two months once seasonal rains start.

But the refugees' greatest fear is for their own security. Even across the Chad border, they are not guaranteed sanctuary from the ravages of their own government. In February, three people were killed and about 50 injured when bombs from a Sudanese aircraft landed just over the border.

In an effort to protect refugees from cross-border raids, UNHCR, the UN refugee agency, said on Tuesday that it had moved more than 31,000 Sudanese refugees deeper into eastern Chad.

According to the UN report the Chadian military has engaged in battles with Janjaweed militiamen who slip across the border to harass refugees and steal cattle. In a recent exchange of fire, two Chadian soldiers died and one was injured.

President Bashir described the Janjaweed as rebels not supported by the government - an account disputed by many workers and diplomats. The Janajweed are heavily armed, their leaders are in provincial offices, use satellite phones and drive government jeeps.

"They are not out-of-control bandits," said Jemera Rone of Human Rights Watch. "They work in close co-operation with the government forces. They loot and rape and nobody is allowed touch them. It's open season on all the ethnic communities."

On Monday, the Sudanese Humanitarian Affairs Minister, Ibrahim Hamid, led a rare media tour of selected towns in Darfur. He said the government would reconstruct areas hit by the fighting. "As you can see, the psychological effect of this ceasefire is tremendous and since Sunday there has been no violation of this ceasefire," he said in Nyala town.

Mr Hamid refused to comment on the government's refusal to issue a visa to Jan Egeland, the UN's chief humanitarian co-ordinator. Mr Egeland has described the violence against Africans in Darfur as "ethnic cleansing, but not genocide" and termed the situation "one of the most forgotten and neglected humanitarian crises".

In its conclusions, the UN report called for an international commission of inquiry to establish the scale of the crimes against humanity in Darfur, and the complicity of the Sudan government in the atrocities.

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