A rogue military commander who oversees the eastern half of Libya has handed control of vital oil facilities to a rival of the U.N.-backed government in Tripoli, potentially escalating the country’s yearslong civil war. The announcement by Field Marshal Khalifa Haftar’s forces on Monday injected fresh uncertainty into the global oil market and sets up a possible showdown between a government allied with the commander in the country’s east and the rival government in the western capital Tripoli, which is backed by the U.S. and the United Nations. If it holds up, the decision would be one of the most serious blows in years to the Tripoli government and to efforts at reunifying Libya, which descended into turmoil following the uprising that toppled Moammar Gadhafi in 2011. Rival Libyan leaders including Mr. Haftar and Prime Minister Faiez Serraj had agreed at a summit in Paris in May to hold […]