The death toll among United Nations peacekeepers in Haiti in a massive earthquake could be the largest number ever killed during a mission by the international body once formal casualty figures are established, according to dpa. The mission chief, Hedi Annabi, his deputy Luiz Carlos da Costa, and at least another 100 UN personnel were unaccounted for Wednesday, a day after an earthquake with magnitude of 7 on the Richter scale struck the impoverished Caribbean nation. UN Undersecretary General for Peacekeeping Alain LeRoy said in New York that the UN still had no information about the fate of those unaccounted for. "It"s a profound concern for us," LeRoy said. The UN stabilization mission in Haiti, known by its French acronym MINUSTAH, is housed in a five-storey concrete building in the Haiti capital Port-au-Prince. The building is across the street from the Christopher Hotel, a major residence for UN staff, which sits atop a fault line. Both of the buildings, which are among the strongest and most important structures in the capital, were destroyed. Some 3,000 UN peacekeepers have been assisting in rescue efforts in and around Port-au-Prince since the earthquake and some 25 aftershocks struck. UN peacekeepers die in mission around the world each year, but the death toll in Haiti could easily top all those killed in the past. MINUSTAH has slightly over 7,000 military troops, most of them from Brazil, and 2,000 police sent by scores of countries to Haiti to train the country"s police force. At least four Brazilian soldiers were killed in the tremblor and the death toll could climb, the military said in Brasilia. MINUSTAH was involved in building democratic institutions in Haiti, and repairing Haiti"s infrastructure after the country was hit by four consecutive hurricane and tropical storms in 2008. The natural disasters destroyed most of Haiti"s agricultural lands and swaths of properties. The mission"s stabilization mandate has been to assist the government of President Rene Preval build a police force to meet security challenges. In a progress report issued late last year, UN Secretary General Ban Ki-moon said Haiti, after five years of the stabilization process, has moved "away from a past of conflict towards a brighter future of peaceful development." But he warned that progress made so far remained "extremely fragile, and is susceptible to setbacks or reversal." A majority of Haiti"s 9 million people still live in poverty and the country depends heavily on international humanitarian and development assistance.