Sweet sour stench of death fills Rwanda: Richard Dowden in Rusumo finds only flies, goats and chickens remain in villages emptied of all humanity by weeks of devastating tribal bloodshed

I DO NOT want to write what I saw. In 10 years of reporting from this continent, nothing I have seen or heard matches the horror of Rwanda.

As we set off to drive across the country, an army major from Zimbabwe with the UN who had fought against Renamo in Mozambique told us: 'I thought Renamo was cruel but it was nothing to what has been done here. Yesterday an officer came from Rusumo but he could not make a report. He could not speak. We have seen things we do not want to remember.'

Perhaps one day someone will try to explain why it happened, how human beings could do these things. At the moment the scenes and images must simply be recorded.

The trail south is agonisingly long, winding through hills of rich blue- green banana plantations and eucalyptus woods. Every inch has been cultivated, but the little homes and huts which make Rwanda the most densely-populated country in Africa are all deserted. It is as if the entire country has fled. A few people still hang around some villages and look at you blankly as you pass, but every home has been ransacked - the scant possessions strewn around outside them. Sometimes you see movement inside the dark homes but it is only goats or chickens which have moved into the deserted huts.

We saw groups of people staggering along the road with baskets, bags or other possessions on their heads. Even the little children tottered along carrying something. Refugees? Returning refugees? Displaced people? One group said it was fleeing, another was returning.

On the road are deserted camps, clusters of thousands of lean-tos of sticks and leaves. These are the homes of people who fled when the war started four years ago. They too are now abandoned, the people fleeing for a second time. As you approach every village along the way, every five or 10 miles, it hits you, a faint sweet sour smell of rotting meat. The bodies are sometimes by the side of the road, still lying where they were gunned or hacked down nearly a week ago. And wherever you see a little pile of possessions scattered in the road you know that you will smell it again. You stop once to look but not again. Flies swarm away from the bodies and here they have a habit of landing directly on your lips or your eyes.

In the larger towns buildings have been smashed by artillery or rocket fire and the doors pulled off most other buildings. We slept on the floor of the town offices at Kibungo and that sweet sour smell woke me many times in the night. A little notice read: 'The charges shall be screwed down in the grenade.' This war has not only been the responsibility of Rwandese.

At last we reached the border with Tanzania, the River Kagera at Rusumo Falls. The river, wide as the Thames and flowing fast, swollen with rains, thunders over rapids and falls beneath a bridge. The river is the colour of oxtail soup and there are lumps in it. Above the bridge you see them coming, about one a minute, sometimes more. And that smell returns again. One looked as if it had been crucified, arms outstretched rigid. Another seemed to be clutching something which had slipped away. Beneath the falls the shiny grey lumps bob around in the eddys and pools; children, women, men. Hundreds and hundreds must have passed down the river in the past week and they are still coming.

Across the border in the rolling savannah is the largest gathering of human beings who have ever fled their homes at one time, according to the UN High Commissioner for Refugees. More than 250,000 of them, and more are still coming. They have what they could carry and when the rain comes down as it does for about two hours every night they simply stand in it and wait for the dawn. The UNHCR is distributing sheeting and the Red Cross and World Food Programme are here, but most people have nothing yet. There is a lake near by for water but food must come by a dirt road eight to 10 hours drive away and it is rapidly being churned into an impassable mud lake in the heavy rain. 'We are terrified of an outbreak of water-borne diseases here,' said Sheila Wilson of the ICRC, 'the logistics of reaching this inaccessible place are a nightmare.'

Who has done these things? The territory we pass through is now controlled by the Rwanda Patriotic Front, the rebel movement which is largely Tutsi. It rapidly advanced after the death of President Juvenal Habyarimana on 6 April and moved down to the border with Tanzania last week. The RPF appears disciplined and does not appear to have been involved in the killings of civilians.

They have been carried out by the government militia, Hutu fanatics, who have killed all the Tutsis in their areas as well as anyone who supported last year's peace agreement between the government and rebels.

But this is not what the people in the refugee camps say. They are mostly Hutus and they say they fled from the RPF which kills all Hutus. Very few say they actually saw the RPF killing people, and only four arrived with bullet wounds according to the UNHCR. Among the refugees are the militiamen who, armed with spears, knives and machetes, have been carrying out the killings and the refugees may be too frightened of them to speak the truth.

But not all these killings can be explained by political or ethnic conflict. They have gone further and deeper. 'They kill you just for looking at them,' said one refugee. A terrible genocidal madness has taken over Rwanda. It is now completely out of control. On the RPF side there is a sort of peace, a peace of death and abandonment. But on the other side as the RPF advances westwards across the country, the militias are continuing to kill. And when the RPF takes the capital, Kigali, which is only a matter of time, the madness may increase.

(Photograph omitted)