JABALIYA, Gaza Strip (AFP) - Seven Palestinians were killed in fighting in the northern Gaza Strip, a day after Prime Minister Ariel Sharon ordered the army to step up a massive raid to stop militant rocket attacks on southern Israel.
The latest campaign, codenamed "Days of Penitence", intensified after two Israeli toddlers were killed in Sderot, less than a kilometre (a mere half mile) across the Gaza Border.
"The activity in Gaza has one clear overriding aim -- to prevent the firing of Qassam rockets at Sderot and the firing of mortar shells at Jewish settlements in Gaza," Defense Minister Shaul Mofaz said while meeting troops about to be deployed in the northern Gaza Strip Friday afternoon.
"This activity will take time -- it's not easy, it's complex," he warned.
Forty-five Palestinians have been killed over the past three days along with two soldiers and a woman settler in one of the bloodiest battles since the Palestinian uprising started four years ago.
Troops were preparing to take control of a six-kilometer (four-mile) deep buffer zone in the northern Gaza Strip to keep militants out of rocket range of southern Israel, a close aide to Sharon told AFP.
The aide said the army could "be more aggressive" if militant rocket attacks continued.
Two rockets did hit Sderot Friday, but without causing any casualties, the army said.
The Islamic militant group Hamas generally claims most strikes on southern Israel but it was the Popular Resistance Committees -- a small faction mostly made up of former activists of Palestinian leader Yasser Arafat's mainstream Fatah movement -- which said it was behind Friday's attack.
Thirty-five tanks were seen entering the town of Beit Hanun at dawn Friday, while another 30 were seen pushing into Beit Lahiya and 30 more spotted moving into the eastern sector of the Jabaliya refugee camp, residents said.
Five of Friday's seven Palestinian victims died in two air raids on Jabaliya, sources on both sides said.
Two were Hamas militants. An army spokeswoman said they were about to fire a Qassam rocket.
Palestinian witnesses said an unmanned plane had fired on the Hamas men.
Medics said at least 14 people had been wounded in the two air strikes and that a third one, also on Jabaliya, had wounded another person.
Two more Palestinians were killed as they attempted to storm the Erez border crossing between the northern Gaza Strip and Israel.
They were part of an eight-strong commando that was "armed and carrying a 30-kilogramme (66-pound) explosive charge," Israeli military sources said. The others were nabbed by the army.
The botched attack was jointly claimed by Hamas and the Al-Aqsa Martyrs' Brigades, a militant group affiliated to Fatah.
The latest deaths brought the overall toll since the start of the Palestinian uprising to 4,400, including 3,376 Palestinians and 953 Israelis, according to an AFP count.
The large-scale offensive sparked international concern with Russia calling on Israel to refrain from using "indiscriminate" force while urging the Palestinians not to resort to "terrorist acts against Israel."
France said it was "deeply concerned" by the flare-up and that "recourse to violence is not a solution" for either sides.
Palestinian foreign minister Nabil Shaath expressed dismay at a call by US Secretary of State Colin Powell Thursday for an end to the uprising, saying he "would have done better to call on Israel to stop its aggression against the Palestinian people."
The UN Relief and Works Agency for Palestinian refugees (UNWRA) accused the army of taking over schools while pupils were still in class, and using them as firing positions.
"They have now taken positions in these three schools and are using them as a military camp for their ongoing campaign, using them also as firing positions," UNRWA spokesman Matthias Burchard said in Geneva.
"UNRWA strongly protests the totally unacceptable misuse of clearly marked UN installations and calls on the Israeli military to respect the neutrality of these places."
Israel's security cabinet Thursday approved a broadening of the Gaza raid, which it said was open-ended but would not be "a permanent occupation".
There have been mounting calls from ministers for a new "Defensive Shield-style" operation in the Gaza Strip, public radio said.
Launched in March 2002, that operation saw the army reoccupy most of the West Bank in a bid to detain Palestinian militants and end a spate of suicide bombings.