Jihadists have murdered five aid workers who they abducted last month in north-east Nigeria.

The humanitarian agencies Action Against Hunger and International Rescue Committee have confirmed that their employees were among the dead.

The militants abducted the five men in Borno State in June. A video was released last month in which the hostages identified themselves.

Nigeria’s President Muhammadu Buhari has blamed the Islamist militant group Boko Haram for the deaths.

Mr Buhari pledged to bring the killers to justice. He said his government would ensure the group is wiped out from north-eastern Nigeria.

Action Against Hunger said it deeply regretted that its calls for the release of the aid workers were not answered.

The International Rescue Committee said it was deeply saddened and heartbroken by the news.

Aid workers have been repeatedly targeted by jihadists in north-eastern Nigeria, where a decade-long conflict has fuelled a major humanitarian crisis.