A joint statement by the UN children's agency, Unicef, and five other groups says 800,000 children died of the preventable lung disease last year, calling it a forgotten epidemic.

They are urging governments to step up investments to counter pneumonia which can be prevented through vaccination, and treated with antibiotics.

Nigeria is the worst affected country, with 430 child pneumonia deaths every day.

India, Pakistan, the Democratic Republic of Congo and Ethiopia also experience a high number of cases.