Khartoum, Sudan, Aug 12, SPA -- The U.N. envoy to Sudan says a lack of security in strife-torn Darfur will prevent more than 1million displaced people from voluntarily returning to homein the next three weeks. Jan Pronk, the world body's special representative toSudan, on Wednesday also urged this country's government todo more to end the 18-month conflict in western Sudan. Addressing reporters in the Sudanese capital in his firstnews conference since assuming his position June 18, Pronkdescribed the Darfur situation as a "tragedy". --SPA1145 Local Time 0845 GMT www.spa.gov.sa/191181