UNITED NATIONS - The United Nations said on Thursday at least 36 of its personnel were killed in this week's earthquake in Haiti, the worst loss of life the world body has ever suffered in a single incident.

Speaking to reporters via video link from the Haitian capital Port-au-Prince, senior U.N. official David Wimhurst said four U.N. police officials were among the dead, along with 13 civilian staff and 19 military personnel.

Sadly, we must expect ... we will start to recover more bodies, Wimhurst said.

U.N. Secretary-General Ban Ki-moon said earlier that around 150 U.N. staff remain unaccounted for. He added that he had no news about the fate of the head of the peacekeeping mission in Haiti, Hedi Annabi of Tunisia.

Haitian President Rene Preval said on Wednesday that Annabi was dead. But U.N. officials later cast doubt on his remarks, saying they had no information to confirm it.

Annabi was in the five-story U.N. peacekeeping mission's headquarters in Port-au-Prince when it collapsed during the earthquake, which struck at 5 p.m. on Tuesday. U.N. officials said he was among those trapped in the rubble and it was not clear if he was alive or dead.

Ban and Wimhurst made clear that as well as efforts to rescue its own people, the United Nations was still working to maintain law and order and deliver aid.

The U.N. force, which includes about 9,000 troops and police from more than 40 countries, was sent to the country in 2004 to try to bring stability after President Jean-Bertrand Aristide was ousted by armed gangs and former soldiers.

It has supported efforts to create a democratic process, run programmes to disarm militant groups and helped the Haitian police. Haiti has been run by President Rene Preval since May 2006, when it returned to constitutional rule.
Ban said that U.N. humanitarian affairs chief John Holmes would issue an appeal, probably on Friday afternoon, for emergency funds for Haiti, although he did not say how much would be requested.

The fate of Haitian nationals employed locally by the United Nations was unknown and was also of concern, Elisabeth Byrs, a Geneva-based spokeswoman of the U.N. Office for the Coordination of Humanitarian Affairs (OCHA), said.

Bomb attacks on the U.N. offices in Algiers in December 2007 killed 17 staff, previously the worst single event for the United Nations in its 65-year history.

Tens of thousands of people were feared dead and many were believed still trapped alive in rubble after the 7.0 magnitude quake hit the capital of the Caribbean nation on Tuesday.

The U.N.'s World Food Program is checking its warehouses to see whether supplies have been looted or damaged, according to Charles Vincent, director of WFP's office in Geneva.

It hopes on Thursday to distribute rations to 2,400 people in Port-au-Prince, a drop in the bucket, but a start, he said.

Most of the population has not had food for a whole day yesterday. As a result, insecurity is feared and obviously MINUSTAH will be trying to control that situation, he said.

(Additional reporting by Stephanie Nebehay in Geneva and Patrick Worsnip at the United Nations, editing by David Storey)

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