Israel and Hamas Maintain Cease-Fire, After a U.S.-Egypt Push Gaza City residents celebrated the cease-fire, which ended the eight days of conflict but did not resolve many underlying issues. CAIRO - Under intense Egyptian and American pressure, Israel and the Palestinian militant group Hamas halted eight days of bloody conflict on Wednesday, averting a full-scale Israeli ground invasion of the Gaza Strip without resolving the underlying disputes. By early Thursday, the truce seemed to be broadly holding and both sides claimed victory. With Israeli forces still massed on the Gaza border, a tentative calm descended after the announcement of the agreement. The success of the truce will be an early test of how Egypt's new Islamist government might influence the most intractable conflict in the Middle East. In southern Israel, the target of more than 1,500 rockets fired from Gaza over the past week, wary residents began to return to routine. But schools within a 25-mile radius of the Palestinian enclave remained closed and thousands of soldiers mobilized for possible ground invasion remained along the Gaza border. The military said that a decision regarding the troop deployment would be made after an assessment of the situation later Thursday. A rocket alert sounded at the small village of Nativ HaAsara near the border with Gaza on Thursday morning, sending residents who skeptical from the start about the cease-fire running for shelter but the military said it had been a false alarm. Israel Radio said a dozen rockets were fired from Gaza in the first few hours of the cease-fire, but Israeli forces did not respond. In the rival Twitter feeds that offered a cyberspace counterpoint to the exchanges of airstrikes and rockets, the Israel Defense Forces said they had achieved their objectives and the armed Al Qassam Brigades in Gaza said Israeli forces had "raised the white flag." After more than a week of nights punctuated by the crash of aerial and naval bombardment and the sound of outgoing missiles, reporters in Gaza said the night had been quiet. At the same time, Israeli security forces said on Thursday that they detained 55 Palestinian militants in the West Bank after earlier confrontations. The army said the detentions were designed to "continue to maintain order" and to "prevent the infiltration of terrorists into Israeli communities." The United States, Israel and Hamas all praised Egypt's role in brokering the cease-fire as the antagonists pulled back from violence that had killed more than 150 Palestinians and five Israelis over the past week. The deal called for a 24-hour cooling-off period to be followed by talks aimed at resolving at least some of the longstanding grievances between the two sides. Gazans poured into the streets declaring victory against the far more powerful Israeli military. In Israel, the public reaction was far more subdued. Many residents in the south expressed doubt that the agreement would hold, partly because at least five Palestinian rockets thudded into southern Israel after the cease-fire began. The one-page memorandum of understanding left the issues that have most inflamed the tensions between the Israelis and the Gazans up for further negotiation. Israel demands long-term border security, including an end to Palestinian missile launching over the border. Hamas wants an end to the Israeli embargo. The deal demonstrated the pragmatism of Egypt's new Islamist president, Mohamed Morsi, who balanced public support for Hamas with a determination to preserve the peace with Israel. But it was unclear whether the agreement would be a turning point or merely a lull in the conflict. The cease-fire deal was reached only through a final American diplomatic push: Secretary of State Hillary Rodham Clinton conferred for hours with Mr. Morsi and the United Nations secretary general, Ban Ki-moon, at the presidential palace here. Hanging over the talks was the Israeli shock at a Tel Aviv bus bombing on Wednesday - praised by Hamas - that recalled past Palestinian uprisings and raised fears of heavy Israeli retaliation. After false hopes the day before, Western and Egyptian diplomats said they had all but given up hope for a quick end to the violence. Tellingly, neither Israel nor Hamas was represented in the final talks or the announcement, leaving it in the hands of a singular partnership between their proxies, the United States and Egypt. There were immediate questions about the durability of the deal. Hamas, which controls Gaza, has in the past not fulfilled less formal cease-fires by failing to halt all missile fire into Israel by breakaway Palestinian militants. Neither side retreated from threats to resume the conflict if the deal fell through, and both said they had only reluctantly agreed under international pressure. In a televised news conference, Prime Minister Benjamin Netanyahu of Israel declared that some Israelis still expected "a much harsher military operation, and it is very possible we will be compelled to embark on one." David D. Kirkpatrick reported from Cairo, and Jodi Rudoren from Gaza. Reporting was contributed by Fares Akram from Gaza, Isabel Kershner and Ethan Bronner from Jerusalem, Mayy El Sheikh from Cairo, Rick Gladstone from New York, and Alan Cowell from Paris.