NEW YORK - The Palestinian envoy to the UN has called on the Security Council to take "practical steps" to stop the fighting in the Gaza Strip to avert a potential Israeli invasion. The UN said Monday that the Israeli airstrikes heavily damaged the UN headquarters for refugee relief and the special envoy for the Middle East in Gaza. "UN premises must be protected and inviolate," the UN said in a statement. It said Israel has all the coordinates and locations of UN premises in Gaza and the strikes occurred without any warnings and have recklessly endangered UN staff and property. Riyad Mansour and Egypt's UN Ambassador Maged Abdelaziz met with UN Secretary-General Ban Ki-moon and the UN Security Council President, Neven Jurica, the envoy from Croatia, urging them to proceed with demanding an immediate ceasefire from Israel. Mansour said the three-day-old Israeli airstrikes aimed at Hamas-held facilities in Gaza have killed and injured "more than 1,700 people." "There is a consensus (for a ceasefire) here and what we want from the UN Security Council and the Secretary-General is to bring Israel into compliance with the demand for a ceasefire before we face a new situation in the next 24 hours," Mansour told reporters. "We do not want to face a situation in which thousands more people will be killed or injured," Mansour said. Abdelaziz, representing the Arab League, said his group is actively involved in the region to work out the ceasefire, rejecting Ban's criticism that governments in the region have not done enough to end the violence. The 15-nation Council and Ban have called for the immediate ceasefire, opening of crossings into Gaza so humanitarian goods can reach Gazans and the start of a dialogue to end the conflict. Israel, which launched the airstrikes against Hamas on Saturday, said it was prepared for a ground assault against Hamas after calling back some 6,000 Jewish reservists. Israel claims Hamas activists had fired more than 400 rockets and 200 mortars into southern Israel in the past four months. Israel's UN Ambassador Gabriela Shalev said in a letter to the Security Council on Saturday that the airstrikes were aimed at "the terrorists and their infrastructure" in Gaza and were not intended against the civilian population. The UN said Monday more than 340 people have been killed by Israeli airstrikes. Ban issued the call for an immediate ceasefire on Monday after spending the weekend telephoning leaders, urging them to work for a ceasefire and improve the humanitarian conditions in Gaza, which has 1.5 million Palestinians, more than half of whom are children. He called for the observance of humanitarian law in the Israeli-Palestinian conflict. "Israel and Hamas must halt their acts of violence and take all necessary measures to avoid civilian casualties," Ban told a news conference. "A ceasefire must be declared immediately. They must also curb their inflammatory rhetorics." He said dialogue can begin only following a ceasefire. "The regional and international partners have not done enough," he said. "They should do more and use all possible means to end the violence and encourage a political dialogue and emphasize peaceful ways to resolve the differences." Ban said he had been in touch with government leaders around the world this past weekend and continued to hold discussions to resolve the conflict, which has killed more than 340 people and injured hundreds. He said the Israeli government has given him guarantees to reopen crossings into Gaza so that humanitarian and medical supplies can reach the 1.5 million Palestinians in Gaza. Ban said he was still in discussions with the Israeli government to carry out those guarantees. UN humanitarian coordinator chief in New York, John Holmes, said the UN Palestinian refugee office in the Middle East would need 100 trucks of relief supplies a day, but apparently only about 60 trucks reached their destinations.