The UN's humanitarian chief has told BBC Focus on Africa that the "place that worries [him] most" is the central Sahel.

Mark Lowcock of Ocha pointed to conflicts arising from people having to compete for already strained resources - and the combination of "low development", high poverty, accelerating climate change and rapid population growth.

"You're seeing clashes, for example, between farming families and families who make a living through nomadic pastoralism," Mr Lowcock said.
"All of those things, together with the fact that this is not the region where the empowerment of women and girls is advanced as much as in some other places, are causing grievances."

His comments come as the UN hopes to raise $1bn (£770m) with a virtual donor conference hosted with Denmark, Germany and the EU.
Armed militia operate in the Sahel, which has become a frontline in the war against Islamist militancy for almost a decade.

"The extremist groups are one manifestation of that, there's also an uptick in organised crime," Mr Lowcock told the BBC.
He said that people being forced from their homes is "a symptom of these underlying problems".
"Not much short of two million people are now displaced across the region - a massive increase over the last couple of years."