A U.N. human rights expert told a meeting of the General Assembly yesterday that Sudan's bloody civil war, which has pitted the government against the rebel Sudan People's Liberation Army for the past 18 years, has been perpetuated and made worse by international oil companies seeking to exploit the country's petroleum reserves. Gerhart Baum, a human rights investigator appointed by the U.N. Commission on Human Rights, said in his report that the exploitation of Sudan's oil fields by companies registered in Canada, China, France, Iran, Malaysia, the Netherlands, Qatar and Sweden "has led to a worsening of the conflict, which has also turned into a war for oil."