Footage shows one group of men being beheaded on a beach and another group being shot in the head in a desert.

The victims are believed to be members of the Ethiopian Church seized in Libya by IS-linked militants.

The video is similar to previous ones posted by IS, including the beheading of 21 Egyptian Christians in February.

Ethiopian condemnation

The latest tape is 29 minutes long and bears the official logo of the media arm of IS. Its authenticity has not been independently verified.

Ethiopian Information Minister Redwan Hussein said the government was trying to verify the nationalities of those shown in the video.

He also condemned the killings, calling them a crime against humanity.

In the video, a masked militant with a gun is seen making a statement threatening Christians if they do not convert to Islam or pay a special tax.

The latest killings appear to have taken place in two regions of Libya - in the south and the east, the BBC's North African correspondent Rana Jawad reports.

Libya has been torn by a civil conflict and growing violence since last summer, our correspondent says.

She adds that some local extremist groups have pledged allegiance to IS.

IS - which controls large swathes of Iraq and Syria - has in recent months published a number of videos apparently showing the killing of its hostages, drawing condemnation around the world.

(BBC)