South Sudan’s President Salva Kiir and his rival, rebel leader Riek Machar, have signed an agreement to try to end five years of civil war. Under the framework deal, a ceasefire will come into effect within 72 hours. The conflict has devastated South Sudan: tens of thousands have died and nearly four million more - a third of the population - have been displaced by the violence. Previous attempts to end the fighting have failed to hold. Reports say that under the latest deal some political prisoners will be released. Kiir and Machar met for the first time in nearly two years last week. The deal, signed in Sudan’s capital, Khartoum, comes amid pressure from neighbouring countries to end the fighting.