A surge in deadly violence in the Gaza Strip and southern Israel petered out overnight with Palestinian officials reporting that Egypt had mediated a ceasefire on Monday ending the most serious spate of cross-border clashes for months.

Axar.az reports citing Reuters that, the latest round of fighting erupted three days ago, peaking on Sunday when rockets and missiles from Gaza killed four civilians in Israel. Israeli strikes killed 21 Palestinians, more than half of them civilians, over the weekend.

Two Palestinian officials and a TV station belonging to Hamas, Gaza’s Islamist rulers, said a truce had been reached at 0430 a.m. (0130 GMT), apparently preventing the violence from broadening into a conflict neither side seemed keen on fighting.

Israel did not formally confirm the existence of a truce with Hamas and its allied Gaza faction Islamic Jihad, militants that it, like much of the West, designates as terrorists.

Officials in Prime Minister Benjamin Netanyahu’s government spoke in more general terms of a reciprocal return to quiet, with one suggesting that Israel’s arch-enemy Iran - a major funder for Islamic Jihad - had been behind the Gaza escalation.

Suffering under renewed U.S. sanctions and Israeli strikes against its military assets in Syria, Iran may have seen stoking Palestinian violence as a way of telling Israel, “we will get back at you through (Islamic) Jihad and Gaza”, Israeli Energy Minister Yuval Steinitz told the Israeli radio station 90 FM.

Israel’s military said that more than 600 rockets and other projectiles - over 150 of them intercepted - had been fired at southern Israeli cities and villages since Friday. It said it shelled or carried out air strikes on some 320 militant sites.

The violence abated before dawn, just as Gazans were preparing to begin the Muslim holy month of Ramadan.

Rocket sirens in southern Israel, which had gone off continuously over the weekend, sending residents running for cover, did not sound on Monday and there were no reports of new air strikes in Gaza.

Egypt and the United Nations, who have served as brokers in the past, had been trying to mediate a ceasefire.