UNITED NATIONS - With Israel rebuffing international peace efforts, UN Secretary-General Ban Ki-moon is pressing ahead with diplomatic efforts to end the Gaza crisis, his spokesperson said Monday. Spokesperson Michele Montas said that the UN chief was meeting with members of the Security Council, which was unable to reach a consensus during its emergency session on Saturday to bring about an end to the Israeli attacks. At the same time, he was in contact to Arab and Israeli Prime Minister Ehud Olmert. Ban Ki-moon also appealed to the international community to "display the unity and commitment" required to bring the escalating crisis to an end. "Given the crucial juncture at which we have arrived in the search for a ceasefire, I appeal to all members of the international community to display the unity and commitment required to bring this escalating crisis to an end," Ban said in a statement. "I believe the United Nations, in particular the Security Council, has a central role to play in bringing a speedy end to the conflict," he said. Ban voiced regrets at the failure of the Security Council to reach a consensus on ending the Gaza crisis. In Washington, the State Department said the U.S., which blocked the Security Council action on Gaza on Saturday, was pressing for a cease-fire that would include three main elements, including a halt to rocket attacks. "We're doing a lot of work on these three elements," said spokesman Sean McCormack said, adding that the goal is to establish a halt to the violence that would meet Secretary of State Condoleezza Rice's standard of being durable and sustainable. President George W. Bush, however, emphasized "Israel's desire to protect itself." "The situation now taking place in Gaza was caused by Hamas," he said in the Oval Office. AMBULANCES Meanwhile, a top UN relief official said ambulances and medical workers in Gaza are facing increasing difficulty in reaching the wounded -- some are being killed in doing so -- and a "humanitarian breathing space" is vital to ensure that food and medical supplies reach those in need as Israel's offensive entered its 10th day. "Large numbers of people including many children are hungry, they are cold, they are without ready access to medical facilities, they are without access to electricity and running water, above all they are terrified. That by any measure is a humanitarian crisis," UN Humanitarian Coordinator for the occupied Palestinian territory Maxwell Gaylard told a news briefing. "There is an overall atmosphere of fear. More than half of the population are children. The spectre of internal displacement is emerging with growing numbers seeking shelter and already there are several thousand civilians in UNRWA's seven shelters," he said, referring to the UN Relief and Works Agency for Palestine Refugees in the Near East. The UN has raised its concerns with the Israeli authorities at the highest levels, in particular the need for humanitarian access for fuel and food into the Gaza Strip and medical patients leaving the Strip, he added, noting: "We are receiving regular cooperation from those authorities. They are in contact with us not just on a day-to-day basis but even more regularly and we are in contact with them." Gaylard said Palestinian deaths have reached 500 and are rising, and some 2,500 have been injured in the offensive which Israel says it launched to end Hamas rocket attacks against its southern cities and towns. A week of air strikes expanded into a land offensive over the weekend. "Electricity and communications are down over much of the Strip both on account of lack of fuel and damage to critical infrastructure. Over a million people are currently without power, and over a quarter million without running water, some for up to six days," he added. The fuel crossing from Israel at Nahal Oz was opened today for urgently needed industrial fuel and "we hope that this crossing will now remain open in order for sufficient supplies to enter over the coming days, and for the Gaza power plant to continue to operate on a more sustained basis," he said. He stressed the power supply crisis has been exacerbated by damage to 10 transformers and at least 6 electricity lines coming in from Israel and Egypt as a result of collateral damage during fighting. Major priorities include the need to bring in wheat grain in bulk through the conveyor system at the Karni crossing and industrial fuel through Nahal Oz, he noted. "We need a humanitarian breathing space to operate and to ensure that assistance particularly food and medical [supplies] reaches the people," he stressed. "Ambulances, staff, patients must be able to move freely. This includes the ability to leave and seek medical treatments unavailable in Gaza. International medical emergency teams need to be allowed in to support emergency capacity at Shifa hospital." Cash also needs to be replenished in Gaza. "Without cash people cannot procure food, even when it is available. Without cash, UNRWA cannot pay its suppliers and contractors, let alone its 10,000 staff, all of whom are essential if distributions are to take place, shelters to be managed, and operations to be maintained," he added.