Members of the Qassam Brigades, the armed wing of the Islamist movement Hamas, during a guarding shift in the Nuseirat refugee camp in central Gaza Strip on July 20, 2009. Palestinian medical sources said four Palestinians were wounded in all of Gaza City and northern Gaza Strip. Witnesses said several Israeli military vehicles penetrated a limited distance after the resistance fired mortar shells at the Nahal Oz crossing, noting that Israeli artillery fired several missiles towards the homes of citizens. There was sporadic armed clashes between the resistance and the Israeli occupation army soldiers have wounded three Palestinians. Photo By Abed Rahim Khatib