Israeli forces were pulling out of the Gaza Strip on Monday following a tentative truce with Hamas that allowed Palestinians to take stock of the devastating three-week war. Military officials claime that troops and tanks that had poured into Gaza on January 3 as part of an offensive to counter Palestinian rocket attacks were gradually leaving, though they remained ready to tackle any flare-ups in fighting. Israel and Hamas separately declared ceasefires on Sunday, to the relief of Western powers that, while publicly sympathetic to the Jewish state's security concerns, were alarmed by the mounting humanitarian toll in the impoverished territory. The crisis clouded the last days of the Bush administration. It spelled Middle East challenges that U.S. President-elect Barack Obama, who is to be sworn in on Tuesday, may find no less insurmountable than those faced by his predecessors. As Palestinians emerged from hiding, agape at the killing of more than 1,300 fellow Gazans and at the widespread destruction of homes and government infrastructure, the head of the Hamas administration claimed a "popular victory" against Israel. "The enemy has failed to achieve its goals," Ismail Haniyeh said in a speech. Hamas's truce decision, conditioned on Israel withdrawing within a week, was "wise and responsible," he said. According to the Palestinian Statistics Bureau, some 4,000 residential buildings were reduced to rubble during the conflict. Western diplomats have said it could cost at least $1.6 billion to repair the infrastructure damage in Gaza. "I don't know what sort of future I have now -- only God knows my future after this," said Amani Kurdi, a 19-year-old student, as she surveyed the wreckage of Gaza's Islamic University, where she had studied science. Hamas officials, during talks with Egyptian mediators, said the faction demanded the opening of all Gaza's border crossings for the entry of materials, food, goods and basic needs.