A video has emerged purportedly showing the execution of a Nigerian Christian by a young boy from an ISIS-affiliated terror group.

The horrific footage, released by ISIS's Amaq 'news agency', shows a child of around eight years old carrying out the execution in an unidentified outdoor area of Borno, Nigeria.

The child in the video warns other Christians: 'We won't stop until we take revenge for all the blood that was spilled.'

A still from a video clip released by ISIS's Amaq 'news agency', showing a child of around eight years old carrying out the execution of a Nigerian Christian

An image taken from the distressing footage has been shared online by SITE Intelligence Group, an organisation which tracks the activity of jihadist groups.

Director of SITE Intelligence Group, Rita Katz, said of the video: 'There is no end to ISIS's immorality.'

According to Katz, the video was taken in Borno in north-eastern Nigeria and the boy is from the Islamic State West Africa Province (ISWAP) terror organisation.

While ISIS has ramped up its attacks on Christians in recent years, Katz added that the video was also a 'throwback' to the terror group's days of children conducting gruesome executions.

ISIS has routinely used young children, dubbed 'cubs of the Caliphate', to carry out the killings of prisoners in propaganda videos.

The Islamic State's West Africa branch was formed after a faction broke away from Nigerian Islamist group Boko Haram in 2016.

Soldiers stationed in Nigeria's restive northeast have been fighting Boko Haram's decade-long campaign of violence. Jihadis Boko Haram and its IS-affiliated Islamic State West Africa Province faction have recently stepped up attacks on military and civilian targets in Nigeria

Last month, eleven Christian hostages were reportedly killed by ISWAP terrorists in Borno on Christmas Day.

A video released last month showed 13 hostages, 10 believed to be Christian and three Muslim. ISWAP claimed they spared the lives of two of the Muslims

The terror group said they killed the captives to avenge for the killing of their leaders Abu bakr al-Baghdadi and Abul-Hasan Al-Muhajir in Iraq and Syria.

Eleven Christian hostages were killed by Islamic State terrorists in Nigeria on Christmas Day. This still is from a video clip released by Islamic State West African Province on December 25

President Muhammadu Buhari condemned the killings, and urged Nigerians not to allow themselves to be divided by religion. 'We should, under no circumstance, let the terrorists divide us by turning Christians against Muslims because these barbaric killers don't represent Islam and millions of other law-abiding Muslims around the world,' he said in a statement at the time.

Jihadis Boko Haram and its IS-affiliated Islamic State West Africa Province faction have recently stepped up attacks on military and civilian targets in Nigeria.

Boko Haram killed seven people on Christmas Eve in a raid on a Christian village near the town of Chibok in northeast Nigeria's Borno state.