Obamas 'outraged and heartbroken' over Nigeria girls

US First Lady Michelle Obama has said her family is "outraged and heartbroken" following the mass abduction of Nigerian schoolgirls.

In an unusual move, Mrs Obama delivered her husband's weekly radio address to condemn the kidnapping as, "grown men attempting to snuff out the aspirations of young girls".

Islamist militant group Boko Haram says it carried out the attack in north-eastern Borno state.