Gaza’s Health Ministry and witnesses said Israeli troops opened fire as a crowd of Palestinians gathered for humanitarian aid in Gaza City on Thursday, killing at least 20 and wounding dozens. Witnesses and health officials said the shooting took place at a roundabout on Gaza City’s southern edge, where a large crowd had gathered for distribution of food. Footage posted online and confirmed to have been taken on the main road near the roundabout showed hundreds of people fleeing, some carrying boxes of aid, as fire rang out in the background. Men loaded wounded Palestinians onto horse and donk…