According to a UN statement, of the four dead police officers, one was from Argentina, one from Burkina Faso and two from Niger, while 18 others were missing.

Thirty-eight civilian personnel were injured and 160 were missing.
Ban Ki-moon, the UN secretary-general, said Hedi Annabi, the UN mission chief in Haiti, was among those missing, but Rene Preval, the Haitian president, said on Wednesday that Annabi had been killed.

The UN mission in Haiti, spread across the country, comprises about 9,000 peacekeeping troops and international police, as well as nearly 2,000 civilian workers and volunteers.

The force was brought in after a bloody rebellion in 2004 following decades of violence and poverty in the nation.

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Ban said some 3,000 peacekeepers were patrolling Port-au-Prince to help maintain order and assist in distributing humanitarian relief in the wake of the quake.
 
And the UN chief said one of the world body's "biggest challenges" would be to co-ordinate the outpouring of international aid, "to help them to help Haiti to the utmost".

The UN mission in Haiti is not without controversy, however.

Several peacekeepers and Haitians have been killed in clashes between UN troops and armed gangs, and residents have blamed the UN forces for the death of numerous unarmed bystanders in the slum of Cite Soleil.

Eugenia Charles, the executive director of the Fondasyon Mapou, a Haitian human rights organisation, told Al Jazeera that many Haitians were suspicious of the UN mission.

"We can go back and see the number of people they have killed in Cite Soleil ... There is still a lot of resentment.

"[The UN has] been in Haiti since 2004. They've had the opportunity to help in rebuilding infrastructure but many of them spend their time going to beaches," she said.

"They have seen what's needed in terms of roads, in terms of schools, hospitals. They could have done more."