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 desperately needed 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. Israel waged a 22-day war meant to end rocket fire on southern Israel from Hamas-ruled Gaza. Cease-fires declared by both sides Sunday ended an offensive that killed some 1,300 Palestinians and wounded thousands, according to Gaza health officials, and inflicted widespread destruction in Gaza. Thirteen Israelis were also killed. Low-level violence on both sides has marred the cease-fire, and on Thursday, a Palestinian man and girl walking near the shore in Gaza City were wounded by a shell fired from an Israeli gunboat, a Gaza health official said. Another shell landed 100 meters away in an empty area near a UN aid distribution center. And heavy-caliber bullet fire struck at least one house in the area, a witness said. The IDF said it was firing to deter a Palestinian fishing vessel that had strayed off-limits. 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." Israel and Egypt have kept the crossings largely closed since Hamas terrorists seized power in Gaza in June 2007, choking off most supplies to the tiny seaside territory and trapping most of its 1.4 million people inside. Hamas says the borders must be opened as part of any cease-fire deal.