South Sudan’s main opposition party says a peace agreement that ended a five-year civil war has collapsed, following the arrest of its leader Riek Machar a day earlier.

Mr Machar was "in confinement by the government" and his life was "at risk" after "heavily armed vehicles forcefully entered his residence", the party says.

The reported house arrest of Riek Machar, the former bush rebel leader who became South Sudan's First Vice President, marks the latest turn in the turbulent relationship with his rival, President Salva Kiir,