War against Iraq could unleash anti-Christian hatred internationally, endangering lives and the work of aid organisations, the head of the world's second-biggest humanitarian group has warned. Caritas Internationalis' secretary-general Duncan MacLaren reiterated the fears of aid groups that war would affect millions of Iraqis. United Nations-imposed sanctions were affecting 16 million people - more than 70 per cent of the population - and indirectly killing 500,000 children each year. Conflict would worsen the plight of the country's most vulnerable people. In Hong Kong for celebrations marking the 50th anniversary of Caritas here, he predicted that global stability depended on what happened in Muslim-majority Iraq in coming weeks. 'Our great worry is that the West will demonise all Muslims and that people of Islam will then demonise all Westerners, particularly Christians,' Mr MacLaren said. 'That's disastrous news for the world.' Caritas is the humanitarian branch of the Catholic Church. Headquartered in Rome and second in size to the Red Cross and Red Crescent, it does development, relief and social work - combined or individually - in 192 countries. In Iraq, it operates under the French name Confreri de la Charite through various Catholic churches in the country and has 10 centres dealing in large-scale humanitarian work, but concentrating mostly on medical aid. A divide between Muslims and Christians created by an invasion to overthrow Iraqi President Saddam Hussein could hamper the work of Caritas and other religion-grounded groups. They, and other aid agencies, have for months been preparing for a humanitarian disaster. For Caritas, this has meant stockpiling emergency supplies and readying a fleet of mobile ambulances in neighbouring Jordan. Mr MacLaren feared as many as 100,000 civilians would die as a result of a war. 'From our experience, the humanitarian disaster that will occur will be huge,' he said. 'The Pope and other church leaders are opposed to any immediate war in Iraq,' Mr MacLaren said. 'But in Catholic theology, there is the theory of a war being just. 'If Saddam Hussein does have nuclear weapons and is going to use them - if every possibility is used up - then a war could be justified.' For now, though, he said Church leaders did not believe this was the case.