CAIRO ? The U.S. Embassy in Libya said Libyan commander Khalifa Hifter agreed to reopen key oil fields and terminals no later than Saturday, a move that could advance talks between the country's warring sides closer to a political settlement to the yearslong conflict. Powerful tribes in eastern Libya loyal to Hifter have kept export terminals closed and choked off major pipelines since the start of the year. That move aimed to put pressure on their rivals in the U.N.-supported government in the capital, Tripoli, in the country's west. Oil-rich Libya was plunged into...