Tripoli government forces look on during clashes with forces led by Field Marshal Khalifa Hifter south of the capital Tripoli, Libya on Tuesday, May 21, 2019. The U.N. envoy for Libya warned Tuesday that the oil-rich nation “is on the verge of descending into a civil war” that could divide the country and imperil the security of its neighbors and the wider Mediterranean region. (AP Photo/Hazem Ahmed)