The United Nations carried out house-to-house searches in Haiti today in an effort to find an estimated 160 missing UN personnel, dpa reported. The earthquake in capital Port-au-Prince killed at least 39 members of the UN peacekeeping mission there, the agency said in New York. The head of the UN mission in Haiti, Hedi Annabi, and his deputy Luiz Carlos da Costa are still unaccounted for. Both were in the Christopher Hotel that housed other UN personnel when the quakes struck Tuesday afternoon and collapsed the building. Speaking through a video conference from an office in Port-au- Prince, Kim Bolduc, deputy representative for the UN humanitarian coordinator and head of the UN Development Programme in Haiti, said a "great number" of people remained trapped in buildings crushed by the quake and its aftershocks. The 39 dead include police, military and civilians working for the UN mission in Haiti. "We are conducting house-to-house search of our personnel," said Bolduc. The UN system in Haiti was trying to re-organize two days after the 7-magnitude earthquake that collapsed its two main buildings in the capital. UNDP from New York has dispatched three teams to conduct house-to- house searches of those still missing, Bolduc said. She said rescue teams from the United States, France, China and the Dominican Republic have arrived and begun the work of finding survivors and retrieving bodies. Bolduc said "large amount" of relief supplies have also arrived. UN Secretary General Ban Ki-moon described quake-stricken Haiti as "grim" on Thursday as rescuers worked frantically to save people buried under rubble. "I fear it could be very high," Ban said, adding that the next 24 hours are critical to rescue efforts as more time passes since the magnitude 7 quake on Tuesday.