Libya's rival factions on Friday agreed to Dec. 16 as a target date for signing a United Nations-backed national unity government agreement meant to end their conflict. The U.N. has been negotiating for a year to get Libya's two rival governments and armed factions to end their war that has plunged the North African state into chaos four years after rebellion ousted Muammar Gaddafi. Successfully signing an agreement would open the way for the international community to support Libya in the fight against Islamic State, which has gained ground in the chaos and controls the western city of Sirte.