The Islamic State in West Africa Province, ISWAP has released a statement saying the killing of the 11 Christians on Christmas day was to revenge the killing of (ISIS) group top man, Al-Baghdadi.
The footage posted in an online Telegram news channel late on Thursday by ISIL-linked propaganda arm Amaq showed 11 blindfolded men being lined up at an unidentified outdoor location, al-Jazeera reports.
Al-Baghdadi committed suicide in October to avoid capture during a raid by United States special forces on his hideout in the province of Idlib, northwestern Syria.
In recent months, Islamic State in West Africa Province (ISWAP) has intensified its attacks on Christians, security personnel and aid workers, setting up roadblocks on main roads and conducting searches.
A previous video, seen by Reuters News Agency, said the captives had been taken from Maiduguri and Damaturu in Nigeria’s northeast, where fighters have been attempting for years to set up a separate state under Islamic law.
In that earlier video, the captives pleaded for the Christian Association of Nigeria and President Muhammadu Buhari to intervene and save them.
ISWAP split from Nigerian armed group Boko Haram in 2016, pledging allegiance to al-Baghdadi.
It stepped up attacks on military outposts and troops in mid-2018 but has increasingly begun targeting civilians.
The decade-long armed uprising in northeast Nigeria has killed 36,000 people and displaced around two million, according to the United Nations.
The violence had spread to neighbouring Niger, Chad and Cameroon, prompting the formation of a regional military coalition to combat the fighters.