RAMALLAH, West Bank - Five Jewish settlers - four members of the same family and a neighbor - were killed last night after Palestinian gunmen burst into a home and briefly took hostages. Two assailants were killed and eight other Israelis wounded when soldiers stormed the scene.

The raid on the Itamar settlement, north of Ramallah near the West Bank city of Nablus, came as Israeli troops, fulfilling a government order to seize Palestinian territory after two suicide bombings, rolled into towns and villages across the West Bank. Hundreds of Palestinians were arrested and numerous homes were searched.

Early today, tanks poured into the city of Nablus. Israel issued a limited call-up of reserves ahead of what is expected to be a wide-ranging campaign.

Israeli Prime Minister Ariel Sharon cut short a public appearance last night when he learned of the Itamar attack, which came on the heels of two suicide bombings that killed 26 Israelis in 36 hours. An emergency Cabinet meeting was called for today.

Sharon spoke with President Bush for 10 to 15 minutes by telephone; the conversation largely focused on the current round of attacks against Israel.

It was the second infiltration in three weeks into Itamar, home to some of Israel's most militant settlers. On May 28, three teen-age settlers were killed by a Palestinian gunman on a basketball court.

In last night's attack, the gunmen rushed into the unfenced settlement and opened fire as they ran into a house, witnesses said. Inside, they apparently shot to death a mother and three of her children, Israeli state radio reported. A neighbor who rushed to help was also killed. Other children in the large family reportedly saved themselves by initially hiding in bedrooms and the bathroom.

Soldiers who converged on the house shot it out with the Palestinians in a gunbattle that lasted nearly two hours. One of the Palestinians was killed, the army said. A second body believed to be the other Palestinian was found in the ruins of the house, a portion of which caught fire and burned.

"We heard gunfire and felt that this was something more than target practice," settler Yaakov Heiman told Israeli television. "We heard shouting that a terrorist had entered the settlement. ... It is just awful."

Two Palestinian groups claimed responsibility for the attack. One is an armed offshoot of the Popular Front for the Liberation of Palestine, whose leader was assassinated by Israel last year. The other is Al Aqsa Martyrs Brigade, which is affiliated with Palestinian Authority President Yasser Arafat's Fatah movement.

Yesterday, Arafat urged an end to attacks on Israeli civilians. Many Palestinians distinguish between attacks inside Israel and those on settlers and soldiers in the West Bank and Gaza Strip, land captured by Israel in the 1967 Middle East #that Palestinians claim.

Anticipating another Israeli military offensive after a spate of deadly suicide bombings, Palestinians voiced both dread and defiance yesterday.

In Bethlehem, Kalkilya, Jenin, Tulkarm and many villages, tens of thousands were confined to their homes by curfews that the army said would last "until the missions are completed."

In Jenin, more than 2,000 men were rounded up overnight, although most were released by morning. Troops conducted house-to-house searches in many communities as security officials warned that more suicide bombers were heading for Israeli cities.

Israeli forces met with little resistance. Palestinian police and other security officers disappeared from their shattered posts, and militants went into hiding. None of the armed men who are usually a common sight in the streets in Ramallah, the Palestinians' de facto West Bank capital, could be seen yesterday. It was a city visibly hunkering down for the anticipated invasion.

Palestinians seemed to sense that this time, Israeli fury over a wave of deadly suicide bombings is so great that the government might soon unleash a military operation that could dwarf Operation Defensive Shield.

That offensive, launched in March after a bomber killed 29 Israelis attending a Passover Seder, was the largest military sweep through the West Bank since the Israelis captured the area from Jordan in the 1967 war.

Back-to-back suicide attacks in Jerusalem this week that killed 26 Israelis and wounded dozens have triggered a chorus of calls for harsh action.

The Itamar raid was sure to solidify Sharon's resolve.

"We are in the middle of a war," he told a conference in Tel Aviv last night, after being notified of the violence in Itamar. "A hard war, a cruel war that Palestinian terrorists are carrying out against old people, women and children."

Mary Curtius and Tracy Wilkinson write for the Los Angeles Times, a Tribune Publishing newspaper.