In the video released by IS news agency Amaq on Dec 26, 10 among 11 Christian hostages were pushed to the ground and beheaded while one was shot to death.

The IS said it has killed the hostages to avenge the killing of its leader Abu Bakr al-Baghdadi during a raid conducted by the US in Syria in October this year.

The identity of the victims have not been disclosed.

A member of the terror group's media unit has been quoted by BBC as saying, "We killed them as revenge for the killing of our leaders, including Abu Bakr al-Baghdadi and [IS spokesman] Abul-Hasan al-Muhajir."

Condemning the killing, Nigerian President Muhammadu Buhari has urged his countrymen not to get divided on the basis of religion.

In one of his series of tweets, Buhari tweeted, "These agents of darkness are enemies of our common humanity and they don't spare any victim, whether they are Muslims or Christians, and therefore, we shouldn't let them divide us and turn us against one another."

The President added, "I call on all Nigerians to stand united against terrorism and to avoid unhelpful conspiracy theories that serve the interest of Boko Haram terrorists and ISWAP."