Israeli military forces killed eight Palestinians on Friday and two more early Saturday in the northern Gaza Strip in an expanding operation mounted to prevent rocket attacks. Senior Israeli officials said the assault was partly designed to persuade Palestinian civilians to pressure armed groups to stop firing rockets at Israeli towns and Jewish settlements.

The operation, in which 38 Palestinians and two Israeli soldiers have been killed over the past four days, according to local hospital officials, has been the largest and most intense assault by the Israeli military in more than two years. Three brigades with more than 100 tanks and armored personnel carriers are cordoning off the northern Gaza Strip, said Israeli officials, who indicated the attacks could continue for days.

"This operation will go for as long as it takes to stop the firing of the missiles," said Gideon Meir, an Israeli deputy foreign minister. "If we have to go deeper, we will go deeper. . . . If we have to go more forcefully, we will go more forcefully."

The incursion intensified the level of violence in a Palestinian enclave already buffeted by armed clashes and civil tension as Israel's prime minister, Ariel Sharon, seeks to evacuate Jewish settlements in the strip. Sharon has weathered harsh attacks from members of his Likud Party and Jewish settlers over his proposed pullout, while rival Palestinian groups are maneuvering to assume positions of power.

Israeli forces launched the operation -- code-named Days of Reckoning -- late Tuesday night in an effort to prevent Palestinian guerrillas from firing Qassam rockets, crude projectiles with a range of about five miles, into Jewish settlements inside Gaza and Israeli towns near the border. But on Wednesday evening, while Israeli tanks and helicopters were conducting attacks and surveillance operations, Palestinians fired three rockets at the Israeli town of Sderot, about two miles outside Gaza, killing two small children and prompting Sharon to order a much larger military operation.

One goal of the intensified effort is to create "a big threat to the civilian, noncombatant population," said a senior Israeli official who spoke on condition of anonymity because of the political sensitivity of the tactic, "to tell them they are going to pay a price for cooperating with terrorist organizations and to create an environment where there starts to be pressure from within the Palestinians on terror organizations to stop it."

The official said that the Israeli military might destroy houses used to launch the Qassam rockets, adding of the Palestinians, "There's no question they are using their own civilian population" to give cover to guerrilla activities.

A second senior official, who also spoke on condition of anonymity, concurred, saying, "This is our objective, and we're not going to be able to leave Gaza unless we can create such a deterrent."

Since the current conflict between Israel and the Palestinians erupted four years ago, Israeli officials have never openly declared a strategy of using military operations to divide Palestinian society by turning civilians against militant organizations. In the past year, Palestinians in the northern Gaza Strip have conducted a few small protests against militants who use their fields and olive groves as missile-launching sites.

Palestinians described scenes of panic and chaos Friday as residents of the sprawling Jabalya refugee camp who ventured into the streets were repeatedly sent diving for cover when 60-ton Merkava tanks fired rounds into the camp from their main cannons. Overhead, AH-64 Apache helicopter gunships fired missiles along the outskirts of the camp, witnesses said. More than 100,000 Palestinians live in the dense labyrinth of narrow alleys sandwiched between concrete-block apartments.

At the same time, Palestinian guerrillas in black ski masks roamed the camp, laying mines and explosives at major intersections and street entrances. Fighters and residents also piled mounds of sand in the streets in an effort to stop Israeli tanks and armored personnel carriers from entering residential areas.

Israeli officials closed the only crossing between the northern Gaza Strip and Israel before the operation began, barring all nonmilitary personnel from entering or leaving Gaza.

The Palestinian prime minister, Ahmed Qureia, called the Israeli offensive "state terror that deliberately targets civilians" and called for international intervention. Foreign Minister Bernard Bot of the Netherlands, which currently holds the European Union's rotating presidency, condemned the Palestinian rocket attacks on Israel but also accused Israel of a "disproportionate" reaction.

A statement by the human rights group Amnesty International said, "Israel is obliged to ensure that any measures taken to protect the lives of Israeli civilians are consistent with its obligations to respect human rights and international humanitarian law."

White House press secretary Scott McClellan told reporters traveling with President Bush in Pennsylvania that Israel had "the right to defend itself" but also urged "all parties to refocus again on moving forward on the 'road map,' " a U.S.-sponsored peace plan that has been dead for more than a year.

Other Palestinians said they believed Sharon's incursion into Gaza was politically motivated, aimed at discrediting critics who accuse him of giving in to Palestinian militants by proposing to move the approximately 8,200 Israeli settlers out of the area.

Jamil Majdalawi, the Gaza head of the Popular Front for the Liberation of Palestine, asserted in a telephone interview that Sharon wanted to sow as much destruction as possible before pulling out of Gaza.

The Israeli leader, Majdalawi said, was using the rocket attacks as "an excuse. In the past four years all the rockets launched together are not equal to 10 percent of what he does one night in Jabalya."

Palestinian militants have fired about 470 Qassams and other rockets at Israeli towns and Jewish settlements in the past four years, according to Shin Bet, the Israeli intelligence agency. Those projectiles have killed four people, all in the past three months.

Three days of fighting have provided several examples of abuses of the local population by combatants on both sides.

The military gave Israeli television stations video footage from a remotely piloted aircraft that it said showed a vehicle marked "U.N." being used to transport Qassam rockets. Meir, the Foreign Ministry official, called the use of a such a vehicle attacks "horrendous."

Peter Hansen, who heads the Gaza offices of the U.N. Relief and Works Agency, which administers Palestinian refugee camps, said he had not seen the film and had "grave difficulty" believing his agency's workers had helped transport rockets.

Hansen said he had received reports from the Jabalya camp that Israeli forces took over three schools run by his agency. When the soldiers withdrew from the schools, he said, residents reported that Palestinian guerrillas took their places. Hansen said both sides' abuse of the schools was "equally serious."

Special correspondent Islam Abdulkarim contributed to this report from the Jabalya refugee camp.

Israeli tanks and armored vehicles maneuver on the Gaza Strip border ahead of the third day of a large military operation in the enclave.A wounded Palestinian seeks treatment at Jabalya refugee camp. The expanding assault on rocket sites in Gaza has killed 38 Palestinians and two Israelis.