Israeli airstrikes and artillery shelling killed 21 Palestinians across the Gaza Strip Wednesday morning as the military offensive entered its sixteenth day. <br /> <br />More than 640 Palestinians, the vast majority of whom have been civilians, including more than 160 children -- have been killed in the assault so far, while Israel has suffered 29 deaths, 27 of whom have been soldiers. <br /> <br />The Gaza Strip continued to be bombarded from air, land, and sea on Wednesday morning, a day after the the United Nations' Palestinian refugee agency UNRWA accused Israeli of shelling a UN school sheltering the displaced for the second time in two days. <br /> <br />"UNRWA condemns in the strongest possible terms the shelling of one of its schools in the central area of Gaza," it said in a statement.
