UN Secretary General Ban Ki-moon today said it was "unacceptable" that Sri Lankan authorities have failed to prevent the disruption of United Nations activities in that country, according to dpa. Ban ordered Neil Buhne, the UN special envoy for Sri Lanka, to return to UN headquarters in New York for consultations and to close the UN Development Programme office in Colombo. Sri Lanka's Construction and Housing Minister Wimal Weerawansa led a hunger strike in front of the UN office in Colombo to protest Ban's appointment of a three-member panel to investigate the alleged killing of civilians by government troops during the civil war. "The secretary general finds it unacceptable that the Sri Lankan authorities have failed to prevent the disruption of the normal functioning of the UN office in Colombo as a result of unruly protests organized and led by a cabinet minister of the government," a UN statement said. "The secretary general calls upon the government of Sri Lanka to live up to its responsibilities towards the United Nations as host country, so as to ensure continuation of the vital work of the organization to assist the people of Sri Lanka without any further hindrance," it said. The panel is mandated to advise Ban on measures to deal with the Sri Lankan government's accountability for its actions during the final stage in the 26-year civil war to defeat Tamil Tiger rebels last year. Thousands of civilians were reportedly killed.