Militants in the Hamas-ruled Gaza Strip bombarded southern Israel with rockets and mortars on Sunday, striking an empty school and a score of other targets, as diplomats scrambled to keep a new convulsion of Israeli-Palestinian violence from escalating.

Senior Israeli officials met late into the night to discuss how to proceed with retaliatory operations against Gaza militants, who they say triggered the latest round of hostilities on Thursday with a roadside ambush along the Israeli-Egypt border that killed eight Israelis.

Military spokesman Brig. Gen. Yoav Mordechai said Israel’s current response to the surge in violence — airstrikes that have killed 15 Palestinians, most of them militants — was not its final word.

Israel “will not hesitate” to widen its military operation if necessary, he told Israel Radio. “We will see how things develop on the ground,” he said without elaborating.

At midday, Israeli aircraft struck Gaza once again, the military said. It did not immediate disclose its target. Palestinian hospital officials reported one person was wounded.

Israeli troops also rounded up 50 Hamas activists in the West Bank in a sweeping overnight raid, Palestinian security officials said.

Diplomats scrambled to try to prevent the violence — the deadliest since Israel went to war against Gaza militants 2 1/2 years ago — from spiralling out of control.

Yaser Otham, the Egyptian representative to the Palestinian Authority, told Voice of Palestine radio that Cairo was “in contact with all parties to restore the truce in Gaza.”

Militant factions in Gaza confirmed the efforts. Talal Abu Tharefeh, spokesman for the small Democratic Front for the Liberation of Palestine, said “all the Palestinian factions are interested in restoring the truce in order to protect our people.”

Gaza militants have dramatically cut back their attacks on Israel since the war, though the rocket and mortar fire has not ceased completely.

Large-scale Israeli military operations against Gaza gunmen would almost certainly create new friction with the Muslim world at a time when Palestinian President Mahmoud Abbas is preparing to ask the United Nations to recognise an independent Palestinian state.

And pictures of a major Israeli offensive in Gaza could hurt the Jewish state’s efforts to minimize world support for the Palestinian statehood bid. The war Israel launched in the seaside strip in late 2008 badly tarnished its international image because of the high civilian death toll.

A spokesman said Mr. Abbas’ Palestinian Authority planned to use the renewed violence to bolster its case for statehood at the United Nations next month.

“An independent Palestinian state is the remedy for violence,” Husam Zomlot said. “It would control its borders and prevent such deterioration from happening.”

Mr. Abbas asserts no such control at this time. Hamas routed his loyalists in a violent 2007 takeover, and a reconciliation pact the two sides signed in May has stalled.

Hamas opposes both peacemaking with Israel and Mr. Abbas’ statehood bid. Israel and the U.S. do not see that largely symbolic route, which Mr. Abbas chose after a prolonged deadlock in negotiations, as a way out of decades of violence that reignited last week.

Since Thursday’s ambush, militants have fired some 100 rockets and mortars on southern Israel, killing an Israeli man and seriously wounding two other people on Saturday. No serious injuries were reported Sunday.

Egypt was drawn into the current round of violence after at least three of its security forces were killed as Israeli troops pursued militants involved in the ambush along the Israel-Egypt border. Cairo initially threatened to withdraw its ambassador to Israel but relented after Israel apologised.

Diplomats in Cairo and Jerusalem said the U.S., France and Germany had worked with the Israelis and Egyptians to end the diplomatic spat. They spoke on condition of anonymity in order to discuss ongoing diplomatic efforts.

In the Egyptian capital, however, popular anger against Israel simmered, and protesters gathered outside the Israeli Embassy for a third day on Sunday, demanding the expulsion of the Israeli envoy who is now vacationing abroad.

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