Video from a Gaza media agency appears to show the moment a shell killed four boys playing on a beach.<br/> <br />Palestinian health workers said the shell was fired from an Israeli gunboat off Gaza's Mediterranean coast.<br/> <br />The boys, aged between 9 and 11, were all said to be from one family.<br/> <br />Another youngster was wounded.<br/> <br />The Israeli military's said in a statement it will investigate the circumstances of the incident on Wednesday.<br/> <br />The beach area's been frequently shelled since Israel began its offensive on July 8th in response to cross-border rocket attacks.<br/> <br />On the same day four members of the same family were among six Palestinians killed in the Khan Younis area of Gaza.<br/> <br />Israel says it warned residents in several areas of the Gaza Strip to evacuate their homes ahead of military operations.<br/> <br />As the conflict continued on Thursday the toll of Palestinians killed stood at 216, most of them civilians, according to Gaza health officials.<br/> <br />In Israel, o
