As Israel pushes ahead with its offensive against Hamas it has demanded the militant group be prevented from re-arming as a pre-condition for a ceasefire. The incursion is aimed at ending the threat of rocket attacks on Israel.The onslaught continued overnight with five people killed in two separate strikes on UN schools. UN officials say hundreds of Palestinians have sought refuge from the combat in their schools. Tanks have also entered Khan Younis, a Hamas stronghold and the Israeli navy is now also involved in the assault, shelling targets in central Gaza. More than 560 Palestinians have died in the 11-day-old conflict. Four Israeli soldiers were killed in two separate so-called friendly fire incidents early on Tuesday. Five Israeli soldiers have now died in the offensive.