Between 30,000 and 40,000 people have fled fighting in Kadugli, the capital of Sudan\'s oil-producing border state of South Kordofan, the United Nations estimated Friday. \"We estimate... that between 30,000 and 40,000 people have fled Kadugli following the events,\" said Elisabeth Byrs, spokeswoman for the UN Office for the Coordination of Humanitarian Affairs. The UN had said that recent fighting in volatile South Kordofan, between Sudanese government troops and members of the former southern rebel group, the Sudan People\'s Liberation Army (SPLA), was currently most fierce in the state capital, home to about 60,000 inhabitants. Rupert Colville, spokesman for the UN High Commissioner for Human Rights, noted that roadblocks put up by fighting forces were also \"preventing medical and humanitarian access\". The spokesman said that a Catholic church in Kadugli, where displaced people were seeking refuge, was also attacked. \"We call on all parties to the conflict to immediately stop the indiscriminate shelling, refrain from attacks on civilians and provide safe corridors for the safe passage of civilians in line with international human rights laws,\" said Colville. \"And humanitarian agencies must be allowed access to the affected population, to provide urgently needed assistance,\" he stressed.