Aid agencies are warning that time is running out to save more than 20 million people who are facing famine across Africa and the Middle East.

The UN says the crisis in Nigeria, South Sudan, Yemen and Somalia threatens to be the worst in 60 years.

In northern Nigeria, the risk of famine is made worse by fighting with the Islamic group, Boko Haram.

Clive Myrie reports from an emergency feeding centre in Nigeria, where hundreds of children are getting urgent help.