Several captives regained their freedom on Monday after spending months in captivity.
Islamic State West Africa Province (ISWAP) has released several humanitarian workers and civilians abducted during attacks in Northeast Nigeria.
According to a source the aid workers were freed by the group on Monday alongside other civilian captives, after negotiations.
Among those released is a staff of the United Nations High Commission for Refugees abducted along the Damaturu-Maiduguri road in Jan.
The group also released a senior Christian cleric Reverend Zango and one Barka Wasinda, a former staff of the Nigerian Ports Authority and some aid workers abducted from a facility in Dikwa in March.
Dikwa, which lies about 90 kilometres from Maiduguri, the Borno state capital, was targeted in a series of attacks in March, April and May, and recently in June.
During the attack in March, the terror group overran the town, destroyed support facilities, including a primary health care centre, and also laid siege at the United Nations humanitarian hub, which forced aid workers to seek shelter in a bunker.
The United Nations suspended operations in response to the attacks on humanitarian operations in Dikwa and Damasak, affecting humanitarian assets and personnel.
More than 37,000 people have been killed, and millions have been displaced by the Boko Haram conflict, according to the Council on Foreign Relations’ security tracker.