Ban Ki-moon expressed gratitude to the UN workers who died
UN chief Ban Ki-moon has paid tribute to the 101 UN "heroes" who died in the Haiti quake at a ceremony in New York.
Mr Ban, his voice breaking at times, said: "We will never forget you. We will carry on your work."
Hundreds of UN workers joined relatives of those who died for the memorial at the UN headquarters.
Meanwhile, Haitian President Rene Preval is in Washington to seek support from US President Barack Obama on ways to boost Haiti's battered economy.
Mr Preval has said the first phase of the crisis caused by January's massive earthquake was over.
He said he would thank President Obama for the food aid Haiti had received, but that outside aid was now in danger of discouraging Haitian commerce, so the emphasis should be on creating jobs to kick start the economy.
More than 222,000 people died and about a million were made homeless after the 7.0 magnitude quake on 12 January.
UN Haiti mission chief Hedi Annabi and his deputy, Luiz Carlos da Costa, were among those who died when the UN headquarters in Port-au-Prince collapsed. It was the greatest loss of life in a single event for the UN in its history.
The ceremony began with pictures of those who died interspersed with footage of Haiti after the earthquake.
A minute's silence was held and a table was set with 101 candles.
In what correspondents say was his most emotional speech since taking office in January 2007, Mr Ban began by bowing deeply to those watching.
"Dear colleagues, dear friends, above all to families of those to whom we sadly bid farewell, we have suffered the greatest loss in our history," he said, his voice breaking.
"Gratitude fills this chamber - profound thanks that our world and our lives were touched by the grace and nobility of these 101 UN heroes."
He added: "We honour 101 unique paths that joined in Haiti to write the larger story of the United Nations."
Haiti's UN Ambassador Leo Merores said it was tragic that the quake "snatched away from us those who worked for peace and development".
"Their memory will be... an additional reason to encourage us to continue and to complete the work that they started," he said.
"Their sacrifice will not have been in vain."