Two of the four people killed were a truck driver and his assistant.
The terrorists attacked one of the WFP's military-escorted convoy of food trucks which was taking supply to an internally displaced persons (IDP) camp in Ngala village in Gamboru-Ngala Local Government Area of Borno.
According to the organisation's Communication Officer at the Maiduguri area office, Adedeji Ademigbuji, two of the four people killed were the truck driver and his assistant.
He said, "WFP can confirm that a convoy escorted by the Nigerian military including WFP hired trucks was the subject of an attack by armed groups 35km southwest of Ngala in Borno State on Saturday (16 December).
"Four people, including the driver of a WFP-hired truck and a driver's assistant, were killed in the incident. WFP extends its condolences to the bereaved families.
"WFP is working with the authorities to determine the whereabouts of the trucks."
According to a report by Premium Times, sources familiar with the attack confirmed that three other people were abducted by the gunmen, while another source reported that they also burnt one of the food trucks.
Since the insurgency of the terrorist group escalated after a 2009 crackdown by the military, Boko Haram, chiefly under the leadership of Abubakar Shekau, has been responsible for the death of over 20,000 people and the displacement of more than 2.5 million scattered across Internally Displaced Person (IDP) camps across the country and its neighbours.
After a massive military operation resulted in the displacement of the group from its primary base in the infamous Sambisa Forest, it has resorted to suicide bomb attacks on soft targets and carried out daring attacks on military bases, with hundreds of captives still unaccounted for.