Two of Libya’s most powerful rival militias have maintained pragmatic truces in a joint effort to beat back the advance of extremist group Islamic State, commanders and political representatives said. The truces have been centered in the country’s west, where armed groups supporting two competing governments have been engaged in fierce conflict for more than a year. The fight has effectively split the country and stirred concerns of a full-blown civil war. The two main militias, originating from the western cities of Misrata and Zintan, agreed to cease-fires that have largely held since June. They are exploring ways to try to halt the march of Islamic State westward out of the central city of Sirte on Libya’s Mediterranean coast. The results of truce talks between rival militias could help determine the fate of the oil-rich nation, beset by infighting since the overthrow and killing of longtime dictator Moammar Gadhafi […]