Images are circulating on social media showing the execution of three Christian men in Nigeria.

International Christian Concern (ICC) reports that the images were shared by Islamic State West Africa Province (ISWAP).

ICC said that one photo showed the men kneeling with their arms tied behind their backs in front of machine-gun wielding executioners while another showed them being shot dead.

It is believed the men were abducted from a vehicle travelling along a highway in Borno state on 3 June. It is reported that Muslim passengers were allowed to leave. The welfare of a fourth abducted passenger is unknown.

The deaths were confirmed by Rev Ibrahim Abako, secretary of the Yobe State Chapter of the Christian Association of Nigeria.

"On behalf of the Christian Association of Nigeria, Yobe State chapter, we condemn in totality the killing of three Christian youth along Damaturu-Biu Road Federal Highway," he told the Nigerian news outlet, Leadership Media Group. 

There has been a spate of Christian killings by ISWAP this year after ISIS issued a call to its affiliates in January to kill Christians "where you find them".

That same month, 12 Christians were killed when ISWAP carried out a string of attacks on rural Christian communities.