The UN has said as many as ten staff members may have died in today's bomb blasts in Algiers.
A number of staff still remained unaccounted for, a spokeswoman said.
Al-Qaeda has claimed responsibility for the two explosions that hit UN buildings in the Algerian capital today.
Algeria's interior ministry has put the overall death toll at 26, but a Health Ministry source said more than 60 people were killed in the attacks.
One bomb struck two UN buildings and a second explosion blew apart a passing bus packed with students.
Road blocks were thrown up around the affluent area where Algeria's highest court and the constitutional council are located.
The local branch of al-Qaeda, previously known as the Salafist Group for Preaching and Combat, has earlier claimed responsibility for a number of deadly attacks, including a series of bombings in the Algerian capital on 11 April that killed 33 people.
One European official said the targeting of a UN building was a significant new departure for the group.
It has previously focused on Algerian state symbols and foreign energy workers.