UNITED NATIONS - A senior UN humanitarian official Wednesday painted a desperate picture of the situation in Gaza, calling for an immediate end to the fighting between Israel and Hamas and warning that "we are in a life or death situation for many people". Without an end to fighting more civilians will be killed, and without a greater opening of crossings from Israel into Gaza for vital supplies such as wheat and fuel, more needy people will be deprived of food and other necessities, Maxwell Gaylard, UN Humanitarian Coordinator in the occupied Palestinian territory, said in a statement. "Conditions for parents and children in Gaza are dangerous and frightening," he stressed as the deadly Israeli airstrikes continued. "It is absolutely crucial that there is an end to the fighting. Without it, more civilians will continue to be killed. Without the violence stopping, it is extremely difficult to get food to people who need it, we cannot assess where the most urgent needs are, and it is too dangerous for civilians to leave their homes to seek urgent medical treatment, buy supplies and assist people in distress." The Coordinator said it was essential that the Karni crossing open today to bring in wheat since the UN Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) had none left for the 750,000 people who need it. "The wheat grain warehouses are empty. We need to get that wheat grain in now. This is a must," he added, noting that Israel had replied to specific requests but that more had to be done. "We need fuel to the power station so that the power plant goes back on. Gaza's hospitals are facing their largest ever trauma caseloads under some of the most adverse conditions imaginable. They must have reliable power," he said. "We are in hourly contact with the Israeli authorities. They are offering their cooperation and we are offering ours. They have been responsive to specific requests, which we appreciate. But the gravity of the situation now demands more. Today, we need that cooperation translated into real results on the ground." In London, Amnesty International voiced concern that an Israeli ground incursion into Gaza could greatly increase casualties in the ongoing conflict with Hamas. It also renewed a call for immediate access to aid workers and observers in the beleaguered enclave, where at least 393 Palestinians have so far been killed in five days of air raids. "A ground incursion into Gaza by Israeli forces could greatly increase civilian casualties," said the group in a statement. In Geneva, the International Committee of the Red Cross also voiced concerns about the humanitarian toll from the violence, saying it had warned both Israelis and Palestinians against violating international humanitarian law. "We are concerned over the mounting number of civilians wounded or killed as a result of the hostilities," said Pierre Wettach, who heads operations in Israel and the Palestinian territories for the International Committee of the Red Cross (ICRC). Meanwhile, UNRWA appealed for $34m to provide life-saving aid to people in Gaza, battered by five days of Israeli airstrikes and months of blockade. "I call on the international community to respond with the promptness and generosity demanded by the desperate situation in Gaza today," said Karen AbuZaid, the head of the agency for Palestinian refugees, UNRWA.