A Norwegian and 10 Nigerians were among the United Nations workers killed in a suicide car bomb attack claimed by a radical Muslim group at the world body's headquarters in Nigeria's capital last week, the UN said.
Authorities have also recovered the bodies of nine non-staffers and three unidentified people.
The bombing in Abuja on Friday killed 23 people.
The UN also said it has flown 12 critically injured workers to South Africa for further medical care.
UN Deputy Secretary-General Asha-Rose Migiro said the dead also included a Kenyan and a citizen of Ivory Coast.
A suicide bomber on Friday rammed through two sets of gates to reach the UN building's glass reception hall.
There, the bomber detonated explosives powerful enough to bring down parts of the concrete structure and blow out glass windows from other buildings in the quiet Abuja neighbourhood filled with diplomatic posts.
The attack was claimed by a sect known locally as Boko Haram, whose name means "Western education is sacrilege" in the local Hausa language.
The sect, which wants to implement a strict version of Shariah law in the nation, has reported links to African terror groups al-Qaida in the Islamic Maghreb and al-Shabab of Somalia.