As violence in the south escalated yesterday with more rocket attacks from the Gaza Strip than any of the previous three days, Egypt stepped up moves to restore quiet.

Senior Egyptian diplomats said that Egyptian intelligence officials began mediation yesterday morning between Israel and Hamas. The main obstacle, they said, was the Palestinian demand that Israel cease its targeted killings and Israel's refusal to do so.

The Egyptian ambassador to the Palestinian Authority, Yasser Othman, said yesterday evening he predicted a cease-fire within 48 hours.

The rockets that landed north of Gedera, for the first time in the current round of violence, brought more than a million Israelis under the threat of rocket fire from Gaza. A total of 52 rockets fell in Israeli territory yesterday, in the fourth day of violence in the south - more than on each of the previous three days.

The Israel Air Force struck early yesterday morning four rocket-launching sites and nine other targets, including weapons storage sites, in the Gaza Strip. The Iron Dome defense system intercepted 11 rockets.

Some 35 Palestinians were injured in the attacks, according to Palestinian sources.

Some 170 Grad and Qassam rockets have been fired at Israel in the four days of the current round of fighting. Most were launched by Islamic Jihad, which has become a key player in the latest escalation.

Schools will remain closed tomorrow in southern communities, leaving about 200,000 children at home in Be'er Sheva, Ashkelon, Ashdod, Kiryat Malakhi, Netivot and Ofakim.

At the Barzilai Medical Center in Ashkelon, it was decided in light of the situation to move patients to reinforced wings of the preemie, children's, oncology and dialysis wards and the out-patients' department.

Since Friday, the IDF has conducted 18 strikes against rocket-launching crews and attacked another 15 targets in the Gaza Strip.

The Israel Defense Forces released footage of the attacks, which show secondary blasts indicating the presence of weapons at the strike sites.

Three morters fell late yesterday morning on the Palestinian side near the Kerem Shalom crossing point into Gaza. The crossing was shut for half an a hour.

A few hours later a rocket was fired at Ashdod, landing in a neighborhood and damaging shops and parked cars.

Iron Dome successfully intercepted some of the rockets, but two landed in populated areas.

IDF officials said the four days of rocket fire were more severe than the last confrontations, in October and in August, and that "the strikes, mainly by the Popular Resistance Committees and Islamic Jihad, are hard but on the other hand, thanks to Iron Dome the damage in Israel was relatively limited."

According to air force officials, under particularly intense rocket fire, Iron Dome loses some of its efficacy, and the current intercept rate is about 80 percent - which the air force says it consideres an "operational achievement."

Amid the mediation effort, an Egyptian parliamentary committee yesterday voted to call on the government to expel the Israeli ambassador from Cairo and recall the Egyptian ambassador from Tel Aviv.

Meanwhile, the air force said yesterday that its fourth Iron Dome battery will go into service in about two weeks.

Air Force officials said they would not be surprised if in the current escalation the Gaza terror groups deployed rockets with a range greater than 40 kilometers.

The army says that despite the targeted killing of Popular Resistance Committees leader Zuhair al-Qaisi, the status of the attack he was planning to carry out in Israel through Sinai is still unknown and the Southern Command can increase its activities in the areas of needed.

Prime Minister Benjamin Netanyahu's bureau yesterday declined to comment on contacts regarding a cease-fire. Speaking yesterday in the Knesset, Netanyahu accused Iran of responsibility for the escalation.