Three United Nations workers were injured Friday morning after a projectile fired from the Gaza Strip into Israel landed near the Karni border crossing and hit a UN building.Palestinians reported three injured from alleged IDF tank fire in the Sajaiye neighborhood east of Gaza City, according to a report by the Ma'an news agency.The IDF denied the report, saying that it was not operating in the area and that the three UN workers were injured from either a mortar or a rocket.