Obama: Africa food security plan is 'moral imperative'

US President Barack Obama has announced $3bn (£1.9bn) of investment in Africa by US companies, aimed at boosting food security and farm efficiency.

Mr Obama said addressing chronic hunger was a "moral imperative, it's an economic imperative and it's a security imperative".

The president's remarks kick off a summit of G-8 leaders near Washington, DC, expected to focus on the debt crisis in Europe.