South Sudan President Salva Kiir and rebel leader Riek Machar agreed to a ceasefire deal Monday in an effort to end 15 months of fighting that has left more than 10,000 people dead. The deal, which was not immediately made public, proposes how the two leaders would share power under an interim government, with Kiir as president and Machar as vice president, according to African diplomatic sources. Both sides also agreed to adhere to a ceasefire that was first signed in January 2013, but has since been broken. Machar said both sides will continue to hold more discussions on the interim government. The world’s newest country has been ravaged by conflict since December 2013, with multiple unsuccessful attempts to end the violence. The two sides must have worked out a transitional government by July, when Kiir’s term runs out. The two leaders have agreed to resume talks on Feb. 20, according to chief mediator Seyoum Mesfin.