At least 10 United Nations employees were believed to have been among those killed in the Algerian capital Tuesday, casualties of two truck bombs that detonated minutes apart - one apparently a deliberate attack on the UN refugee agency. "We now believe that the UN death toll from the Algiers bombing is now at 10," said UN deputy spokeswoman Marie Okabe. "There are still a number of staff that remain unaccounted for. The situation on the ground remains fluid." The mood at UN headquarters in New York was somber; the UN flag flew at half-mast as officials expected the death toll of UN employees to climb. About 175 UN employees worked in Algeria, including about 115 locally based staff, Okabe said.