Macedonian President Boris Trajkovski was killed Thursday when his plane crashed into Bosnian mountains in thick fog, officials said. Irish Prime Minister Bertie Ahern who was holding European Union talks with Macedonia's prime minister in Dublin confirmed his death. Bosnian officials said the executive jet had disappeared from radar screens about 9 a.m. (3 a.m. EST). The 47-year-old president, whose tenure was marked by the 2001 crisis with ethnic Albanian rebels that brought the former Yugoslav republic to the brink of civil war, had been on a short flight to the Bosnian city of Mostar for an economic conference. A government source in the Macedonian capital Skopje said the plane had gone down "somewhere near Stolac," a zone of treacherous winter skies for aviation amid mountains east and north of Croatia's Adriatic port of Dubrovnik. Several staff members were also aboard, he added. "At about nine o'clock this morning the radar lost control of an aircraft," said Zoran Glusac, a spokesman for the Bosnian Serb interior ministry. Local police reported an explosion in the mountains between Stolac and the village of Ljubinje. "The weather conditions were very bad with heavy fog and rain," Glusac said. Police were sent to the crash site on Hrgut mountain. The U.S.-led NATO peacekeeping force in Bosnia, which has helicopters, said it was on standby in case help was requested. **PHOTO CAPTION*** Boris Trajkovski, president Macedonia, speaks at the 58th Session of the General Assembly at the United Nations in New York on Sept. 24, 2003. (Ray Stubblebine/Reuters)