The UN's humanitarian chief launched a firsthand examination Thursday of the devastation wrought in the Gaza Strip by Israel's offensive so the organization can gear up to provide relief to the territory's 1.4 million people. John Holmes called the steep Palestinian casualty toll "extremely shocking" and suggested the UN might ask Israel to compensate it for wartime damage to UN compounds in Gaza. Hundreds of tons of humanitarian aid were destroyed by an Israeli shelling of the main UN compound. "We want to make sure it is properly investigated and that we get proper accountability for it and proper compensation if it is needed, and I think it will be needed," Holmes told reporters at his first stop in Gaza City. On the first day of a five-day trip to the region, Holmes said he was looking at immediate humanitarian needs and thinking about longer-term reconstruction in Gaza. The biggest concerns, he said, are providing clean water, sanitation, electricity and shelter to people displaced by the fighting. Gaza's blockaded border crossings will have to be opened to allow reconstruction to begin, he said. "Goods have to be able to get in freely and in the right quantities, including construction materials, so that reconstruction can start."