Mostar: a town where only the river has running water: Christopher Bellamy enters an outpost where people live in fear and squalor

IT is reckoned to be the worst place in Bosnia-Herzegovina, apart perhaps from Srebrenica. The UN commander, British Lieutenant-General Sir Michael Rose, visits east Mostar today. His visit will probably mean another let-up in the shelling from the Croatian side, as there was on Tuesday and Wednesday, when the UN commander of all the forces in the former Yugoslavia, General Jean Cot, came here and a prefabricated hospital was delivered by the UN.

Normally east Mostar (a Bosnian army and Muslim enclave straggling 5km along the River Neretva and 2km wide) lives - just - under a fusillade of uncannily accurate sniper fire from increasingly skilled marksmen and, the local command alleges, bombs dropped from Croatian helicopters. General Rose will be interested in those reports. Nato's 'Deny Flight' operation is supposed to stop aircraft being used over Bosnia for warlike purposes.

It will be instantly obvious to General Rose why this place, where an estimated 58,000 people have been effectively under siege since May last year, is so lethal. Two thousand, it is believed, have died, mostly civilians. To the south-west, Croat-held Mount Hum overlooks much of the town. The streets are channels for sniper fire. Nothing prepared me for the sheer, terrifying closeness, frequency and precision of the threats when I stumbled out of a Spanish armoured troop carrier. Sarajevo has nothing on the degradation and squalor and total lack of amenities in east Mostar: no water, apart from the River Neretva itself and no power.

For the first few months of the seven-month war east Mostar received no aid. Now it gets some, but bread and beans make the most boring of diets. You can avoid the snipers by moving carefully; night brings some respite from them. They have night sights, the deputy commander of the Bosnian IV Corps told me, but they are not effective.

If a sniper round hits you, body armour is little help. At over a kilometre, a half-inch calibre sniper round will smash armour or take your head right off. The marksmen are skilled. One man was exposed for three seconds and received a bullet through the neck.

You cannot guarantee avoiding the mortar bombs unless you stay underground. Mercifully, the Yugoslavs were fond of reinforced concrete as a building material. In the middle of east Mostar, you would get the impression that it had a population of 50, not 50,000. People live in cellars or ground-floor rooms, dimly lit, and rarely venture out, except to carry water.

The room I visited, where 35 people live, mostly refugees from the west bank of the city, was Dickensian. The walls were blackened by candle smoke; people sat around in blankets.

The Croats hold most of the west bank, which I saw on Tuesday. It still has many of the traits of a normal city, with people walking about and sitting in cafes. Closer to the river, you duck and dive to sniper positions in windowless buildings. In places, the Croats and Muslims hold buildings just a street apart.

Behind the town to the east, two spectacular crags rise: Fortica and a sharp shoulder called Stolac. Behind them is the third, and most powerful, force in the Bosnian slaughterhouse: the Serbs. If they were to take these heights, they would be able to see down into Muslim courtyards, making east Mostar totally untenable. The Bosnian command does not believe this nightmare will happen, in spite of recent agreements between Serbs and Croats. Here, in Herzegovina, the old hatred between Chetnik (Serb) and Ustashe (Croat) is at its most intense; in central Bosnia, the Serbs and Croats have been co-operating against the Muslims.

The capriciousness of the artillery fire is chilling. I slept in a subterranean dormitory just 50 metres away from the spot where three Italian journalists were killed last week. They should have been safe, but died in a mortar attack. .

General Rose will be as appalled by the squalor in Mostar, which will offend his military mind, as much as by the tactical hopelessness of the situation. But what can he do about it? The Bosnian army has ways out to the north, and to Sarajevo, but the Croats control the aid routes.

'It's fascism versus cosmopolitanism,' said Alica Behram, the landlord at our strange hotel. He introduced me to Rusmir Cisic, Mostar's deputy mayor. Mr Cisic was adamant they would not surrender. 'Europe has to realise that here we have a seed of fascism in Bosnia-Herzegovina. I'm wondering how the world could forget so soon Auschwitz and Dachau.

'We have a flag,' he continued, pointing at the Bosnian blue shield. 'Neum (the Adriatic port) was included in our borders. It would be a nonsense for Bosnia Herzegovina to say we want Dubrovnik because Dubrovnik belongs to Croatia. But if we have to lose Neum, then we fight.'

Incredibly, Mr Cisic and the mayor - the 'president', Smail Klaric - are making plans for the future. When school starts later this month, 5,200 pupils will attend. They even plan to start university classes. They have a scheme for spring planting, with seed brought in by the UN High Commissioner for Refugees and the Red Cross. They plan to bring in a full medical infrastructure. Most important, they need just one more container, with water purification equipment. 'We have drunk water from the Neretva for eight months.'

The shooting continued, big 30mm anti-aircraft shells passing over the 'presidency' and mortar rounds exploding to the east. One of the people driven from the west, a middle- aged, bearded man, did not wish to give his name. 'The Croats have much artillery,' he said. 'We just have small arms - rifles and hands - and hearts. We fight.'

(Photograph omitted)