“I am deeply saddened and outraged by the news of the tragic killing of four aid workers who were held captive by armed groups for almost five months,” stated Mr Kallon.
“My thoughts go to their families, friends and colleagues who are enduring unspeakable pain and hardship.”
The four men were amongst the six aid workers who were abducted on 26 July when their convoy came under attack near Damasak, in the Mobbar LGA.
They were working on a health project implemented by the INGO Action Against Hunger. One of the drivers was killed during the attack and another was reportedly executed on 24 September 2019.