Israeli Prime Minister Ariel Sharon has convened top ministers after four Israelis, including three students, were killed in fresh violence.
A resurgence of Palestinian attacks and Israeli raids could damage coordinated international efforts to revive peacemaking after 20 months of conflict, including signs that Washington will set out a negotiating timetable for the two sides.
The Al-Aqsa Martyrs Brigades, an armed offshoot of Yasser Arafat's Fatah movement, has claimed the two attacks which killed four Israelis in the West Bank.
A gunman shot and killed three Israeli students at an Orthodox Jewish high school in Itamar, near the West Bank city of Nablus.
The attacker was shot and killed by a rabbi after shooting at another group of students playing basketbal.
And a few hours before, an Israeli was shot dead in a car north of Jerusalem on a bypass road meant for Israelis to get to and from Jewish settlements without going through Palestinian towns.
The attacks indicated a renewal of Palestinian targeting of settlements.
While Palestinian leader Mr Yasser Arafat has called for an end to attacks in Israel, including suicide bombings, he has not insisted on a halt to raids on settlements, which Palestinians consider part of the Israeli occupation.
Meanwhile, in the West Bank, Israel continued its repeated raids on Palestinian towns.
Israeli forces in jeeps and armoured vehicles moved into Beitunia, a suburb of Ramallah, and surrounded the house of the local Hamas leader, Hassan Yussuf, Palestinians said. They said Yussuf was not at home.
In Bethlehem, Israeli forces enforced a curfew for a third day and continued searches for gunmen.
At the Dheisheh camp, soldiers arrested several Palestinians after discovering a bomb and some weapons in an abandoned building, Palestinians said.
AP