Sarajevo may be left to its fate: Sadako Ogata, the UN refugees commissioner, predicts catastrophe for the 'safe areas' in another winter of war

ZAGREB (Reuter) - Croatia and rebel Serbs agreed yesterday to avert a new Balkan war over a bridge on the Adriatic coast, which Zagreb plans to open this weekend. The Maslenica bridge and Zadar airport on the coast will be placed under UN protection and closed to troops of both sides. Also yesterday, President Franjo Tudjman's office said he would meet Serbia's President, Slobodan Milosevic, in Geneva today in a new peacemaking attempt. Bosnia's President, Alija Izetbegovic, was invited but is not attending.

UNITED Nations aid workers may have to pull out of much of Bosnia and leave hundreds of thousands of civilians to their fates because the combatants are making humanitarian operations too dangerous, Sadako Ogata, the UN High Commissioner for Refugees, said yesterday. Next winter, she said, might see the collapse of Sarajevo and other places that the Security Council has designated 'safe areas' for Bosnia's Muslims.

'If we are unable to alleviate the plight of thousands of victims now, I fear the worst for the months to come. Last year we feared the potential death of 400,000 people. That catastrophe was averted. But what about the coming winter?' she asked.

'My apprehension stems from the intensification of the war and persecution, and the prospect of still more forced population transfers. My despair is caused by the fact that humanitarian organisations are not allowed to bring even minimal relief to those who suffer, and by the impending catastrophe if we have to go through another winter of war.'

After her speech, UNHCR officials said European governments and Japan had pledged dollars 63.5m ( pounds 45m) for the organisation - enough to keep UN aid teams working in Bosnia for another three months and to start preparations for the Balkan winter. But even these donations leave the UNHCR and other aid agencies considerably underfunded for 1993.

More than 1 million Bosnians, mainly Muslims, depend on international aid for survival, according to Chris Paul of the Bosnia Aid Committee of Oxford. Bosnia's pre-war population was 4.4 million, of whom Muslims made up about 44 per cent, Serbs 32 per cent and Croats 17 per cent. But the de facto Serb-Croat partition of Bosnia has left Muslim-led government forces with barely 10 per cent of the republic under their control.

UNHCR officials said Bosnian Croat forces were preventing 10 aid convoys from travelling from Croatia's Adriatic coast to deliver 440 tons of supplies to central Bosnia. They said that the Croats blamed the blockade on Muslim-led forces who have made inroads into Croatian positions in southwestern Bosnia. Sarajevo receives about 40 per cent of its aid supplies by road from the coast, but the blockade is hitting Croat-inhabited parts of central Bosnia.

Serbian forces have impeded aid deliveries by demanding transit visas and road tolls. Female Serbian demonstrators have held up a relief convoy destined this week for the Muslim enclave of Gorazde. Gunmen in many areas delay convoys for days and seize their stocks to stop aid reaching enemy-controlled territory.

Mrs Ogata did not single out any forces for criticism, but emphasised that conditions were especially severe for Muslims in three eastern Bosnian enclaves that fell under Serbian siege last year. She said the world would soon have to arrange mass evacuations of Muslim civilians from Gorazde, Srebrenica and Zepa to avert disaster. 'We want to carry on, but the parties are rendering impossible our work in many areas. Never have the obstacles and risks been so dreadful and unacceptable as during the last two months,' she said.

Other officials said the UNHCR was not contemplating complete withdrawal, but feared its operations would have to cease in particularly dangerous zones. 'If the fighting spreads, then clearly we will have to regroup our staff in fewer and fewer locations until such time as we can start working again,' said Nicholas Morris, Mrs Ogata's representative to former Yugoslavia.