The UN’s special envoy to Libya has warned of the growing strength of the so-called Islamic State militant group in the country.

Martin Kobler told the BBC that the current power vacuum in Libya was creating a risk that IS fighters there could join up with militants elsewhere on the continent.

He said “fragmentation is creating a political vacuum and a military vacuum” which is allowing IS to spread.

“Particularly worrisome [is] the expansion of zones of influence to the south.

“And if they are going further to the south they could team up with terrorist organisations in Niger and Chad, Boko Haram and the like. And that’s why it’s really important to get a government of national unity in place as soon as possible,” Mr Kobler said.

•Photo shows Boko Haram leader Abubakar Shekau.