The United Nations mourned Tuesday 101 of its personnel who were killed by the devastating earthquake in Haiti in January.

'Today, we commemorate the single greatest loss the UN has suffered in its history,' UN Secretary General Ban Ki-moon said in a ceremony at UN headquarters in New York to pay tribute to UN military, civilians and police officers who belonged to the UN mission and who died in the magnitude-7 quake that struck Port-au-Prince January 12.

'We knew them, very personally,' Ban said in the emotional-laden event attended by nearly all top UN ranking officials and personnel. 'We knew their smiles, their songs, their dreams'.

'To those we have lost, let us say: we will never forget you. We will carry on your work,' he said.

A minute of silence was held for the dead, their photographs shown on a giant screen and names were read.

The UN Stabilisation Mission in Haiti had 7,000 military, civilians and police before the quake. UN agencies like the UN Children's Fund and the UN Development Programme were also operating there.

The UN Security Council decided after the quake to send an additional 3,500 military and police to meet new conditions, including security, and assist in the relief efforts to the 3 million Haitians affected by the quake.

An estimated 230,000 people died in the quake, the Haitian government says.