Militants in the Hamas-ruled Gaza Strip fired a barrage of rockets and mortars on southern Israel, striking an empty school and a dozen other targets, as US and Egyptian diplomats were scrambling to keep the new convulsion of Israeli-Palestinian violence from escalating.
Senior Israeli officials met late into the night to discuss the violence, weighing whether to step up retaliatory operations against Gaza militants they say triggered the latest round of hostilities 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.
Palestinian security forces reported that the Israeli military rounded up 50 Hamas activists in the West Bank in an overnight raid. The military had no comment.
The West Bank is ruled by the Western-backed Palestinian President Mahmoud Abbas, who lost control of Gaza to bitter rival Hamas in a violent 2007 takeover. A reconciliation pact the two sides signed in May after years of failed efforts has stalled.
Since Thursday's ambush, militants have fired around 100 rockets and mortars on southern Israel, killing an Israeli man and seriously wounding two other people on Saturday. No serious injuries have been reported from the bombardment early Sunday, the military said.
Diplomats were scrambling to prevent the flare-up in violence from spiraling 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."
Militant attacks from Gaza diminished sharply after Israel launched a punishing, three-week war in the territory launched in December 2008, following years of relentless rocket and mortar fire on its southern communities. Since then, armed factions have largely maintained a cease-fire.
Egypt was drawn into last week's 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 apologized.
Western diplomats in Cairo said Washington was mediating between the Egyptians and the Israelis to try to prevent the violence from exploding. They spoke on condition of anonymity in order to discuss ongoing diplomatic efforts.
An Israeli Foreign Ministry official, speaking on condition of anonymity, said U.S., French and German mediators had been involved in defusing the diplomatic crisis with Egypt.
While the crisis appears to have been defused, Israeli officials say they are not convinced it cannot re-ignite.
In the Egyptian capital, popular anger 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.
Although the military leaders who now rule Egypt have expressed their commitment to the two nations' 1979 peace treaty, anti-Israel sentiment has grown in Egypt since its longtime autocratic leader, Hosni Mubarak, was toppled by a popular uprising in February. Israel is watching closely for signs that Egypt's new rulers might be responding to that sentiment.
Israel relied on Mubarak as a trusted, if cool, ally, maintaining the peace accord despite Egyptian disappointment that it did not lead to peace between Israel and the Palestinians, and a comprehensive Arab-Israeli agreement. Israeli officials are wary about instability in post-Mubarak Egypt and fear a new government that might distance itself further from Israel.