Israeli officials suggested that the army would leave built-up areas and some forces would redeploy inside Gaza, closer to the border fence, to respond to attacks if necessary. Other units will return to southern Israel.

Hamas, for its part, vowed to continue fighting. Sami Abu Zuhri, a Hamas spokesman, told the news agency Maan that “a unilateral withdrawal or redeployment by Israel in the Strip will be answered by a fitting response by the Hamas military arm.” He said that “the forces of occupation must choose between remaining in Gaza and paying the price or retreating and paying the price or holding negotiations and paying the price.”

Mr. Netanyahu thanked the United States, which along with the United Nations appeared to support Israel’s position that Hamas’s actions violated the cease-fire, and he asked for international help to rebuild Gaza on the condition of its “demilitarization.” Israel appears to be hoping that with the support of Egypt and the international community, President Mahmoud Abbas of the Palestinian Authority can control Gaza through a unity government agreed upon with Hamas and take responsibility for security there and for the Rafah crossing to Egypt.

Mr. Netanyahu repeated that his goal was to restore “peace and calm” to Israel and that he intended to do so by whatever means — diplomatically or militarily. “All options are on the table,” he said. But he indicated that Israel would not get caught up again in talk about a negotiated cease-fire with Hamas and Islamic Jihad and would act in its own interests, while seeking support from Mr. Abbas and the international community for what Mr. Netanyahu described vaguely as “a new reality” in Gaza.

Israel has decided not to send a delegation to cease-fire talks hosted by Egypt, at least not now, Israeli officials said. In Washington, Jen Psaki, a State Department spokeswoman, said: “In the end, this particularly bloody chapter will ultimately require a durable solution so that all the fundamental issues, including Israel’s security, can be negotiated, and we will keep working with Israel and other partners to achieve that goal.” She said that Israel had a right to defend itself.