Israeli military forces have launched raids into several areas of the Gaza Strip, killing four Palestinian policemen.
In a series of incursions into Palestinian-ruled areas of the Gaza Strip, Israeli troops, backed by tanks and armored personnel carriers, raided communities searching for militants and weapons.
The army says the raids on Deir al-Balah, Beit Lahia and Beit Hanoun were in response to the firing of a new type of rocket earlier this week from Gaza into Israel.
The operations triggered sporadic gunfights that killed four Palestinian policemen. The Israeli army later pulled out of Deir al-Balah and Beit Lahia, but remains in Beit Hanoun. During the raid on Beit Hanoun, the military imposed a curfew, and arrested alleged militants.
Dozens of children, some carrying school bags, threw stones at tanks and burned tires to protest the incursion into Beit Hanoun. An Israeli army spokeswoman says Beit Hanoun is a stronghold of the militant Hamas movement, and mortars have been fired from the town at Jewish settlements in Gaza.
For the first time Sunday, militants launched Qassam-Two rockets from Gaza into Israel, causing no casualties, but alarming Israeli security officials, because such weapons can reach population centers.
In retaliation, Israeli warplanes earlier this week struck Palestinian security targets in Gaza, and Israeli troops raided Palestinian areas in the West Bank.
The Palestinian public security chief in Gaza, Abdel-Razek al-Majaydeh said, "the re-occupation of the northern Gaza Strip sabotages Palestinian, international and Arab efforts to restore calm." He says Israeli leaders will not be able to "achieve security and peace with tanks and helicopters."
Israeli Defense Minister Binyamin Ben-Eliezer says the Jewish state may re-occupy some Palestinian-controlled areas, if more rockets are fired. Mr. Ben-Eliezer says Israel may setup so-called "security zones" in the West Bank and Gaza, in an effort to prevent rocket attacks.
Such zones in the West Bank could require Israel to take over major Palestinian population centers.