The public execution was captured on video.Masked gunmen, some wearing green armbands associated with the Palestinian militant group Hamas, lined up eight prisoners in the middle of a crowded street in Gaza city on Monday. They forced the men to bend over, pointed their rifles at them and opened fire, leaving their bodies in the dirt.A Hamas internal security official confirmed that the video, which The New York Times geolocated to Gaza City, showed Hamas fighters executing Palestinian rivals in the Gaza Strip. He spoke on condition of anonymity because he was not authorized to speak to reporters.The execution came just days after the start of a ceasefire with Israel on Friday and the withdrawal of Israeli forces in parts of Gaza. According to analysts, Hamas appears to want to assert that...