MAIDUGURI, Nigeria — Three workers for United Nations agencies were among 11 people killed in an attack by armed Boko Haram militants on a military base in northeastern Nigeria, near the border with Cameroon, U.N. officials said Friday.

The International Organization for Migration said “a large number” of Boko Haram members attacked the base in Rann, in Borno state, a day earlier with automatic weapons, rocket-propelled grenades and gun trucks.

At a U.N. briefing in Geneva, IOM spokesman Joel Millman said the two staffers, Ibrahim Lawan and Yawe Emmanuel, were among three humanitarian workers killed along with eight members of police and the military. The U.N.’s humanitarian aid coordinating agency, OCHA, said a third aid worker killed was a doctor consulting for UNICEF.