Israel is planning to pull all its troops out of Gaza ahead of Barack Obama's inauguration, political sources have said. Meanwhile, UN Secretary-General Ban Ki Moon is visiting the Hamas-ruled Gaza Strip to see the devastation following Israel's 22-day offensive. He is the highest-ranking international figure to visit the territory since separately declared ceasefires by Israel and Hamas ended the Israeli offensive and Palestinian cross-border rocket attacks three days ago. Mr Ban, on a Middle East peacemaking mission, will also visit southern Israel. World leaders are keen to cement a truce and avoid any more bloodshed in Gaza where more than 1,300 Palestinians were killed in Israel's air and ground strikes launched on December 27 with the declared aim of ending rocket attacks. Gaza's infrastructure has been left in ruins, with a repair bill estimated at about £1.3 billion. Hamas said 5,000 homes, 16 government buildings and 20 mosques were destroyed and that 20,000 houses were damaged. Israel has said militants hid weapons inside the mosques. Palestinian militant groups said 112 of their fighters and 180 Hamas policemen were killed. Israel said ten of its soldiers and three civilians were killed in rocket attacks. Gaza medical officials said the Palestinian dead included at least 700 civilians. Israel, which accused Hamas of endangering non-combatants by operating in densely populated areas, said hundreds of militants were among the dead. In Geneva, World Health Organisation head Margaret Chan warned of a looming health crisis for many among the 1.5 million Palestinians living in Gaza. Ms Chan said she was "deeply concerned" about an interruption of immunisations and other life-saving care in the territory, and of the availability of only 2,000 hospital beds in Gaza. Saudi Arabia has pledged $1 billion (£700,000) for rebuilding and the European Union said the bloc's foreign ministers planned to meet in Brussels to discuss humanitarian aid.