The United Nations has condemned the killing of five aid workers by militants in Nigeria.

The militants abducted the five men in the north-eastern Borno state in June. Nigeria’s President Muhammadu Buhari has blamed the Islamist militant group Boko Haram for their deaths.

UN humanitarian coordinator in Nigeria, Edward Kallon, said "it is unacceptable that those who are trying to help are being attacked and killed".
"This incident will not deter the international community from providing aid to millions of Nigerians who desperately need assistance in the north-east," he said in a statement.

He also expressed concern at the number of checkpoints set up by armed groups along main supply routes.

"These checkpoints disrupt the delivery of life-saving assistance and heighten the risks for civilians of being abducted, killed or injured, with aid workers increasingly being singled out," he said.

The five aid workers were employees of humanitarian agencies Action against Hunger and International Rescue Committee.
The Islamist Boko Haram group has been carrying out bombings, assassinations and abductions in Nigerians since 2009.