BETHLEHEM, FEB. 3 -- Jewish settlers are becoming more involved in the volatile eight-week-old confrontation between the Israeli Army and Arab residents of the occupied West Bank, where two more Palestinians died today.

This week, a settler was seriously burned when his car was firebombed. Dozens of Jewish cars and buses in the West Bank, especially in this town just south of Jerusalem, have been pelted with stones and bottles. Settlers have retaliated by smashing car windows in one Arab village, setting up illegal roadblocks elsewhere and grabbing alleged stone throwers in actions that some Army officials say they fear could mark the start of an outbreak of vigilantism.

"We're aware of what can happen and we are trying to prevent it," said an Army spokesman. "We've made it clear to the settlers that we are fighting on one front now against the rioters, and if we have to fight on another front against them, we'll have a real problem."

Settlers were involved in an incident Monday in which someone fired on Arab rioters blocking the main highway in the village of Anabta, killing two young men and critically wounding a woman, who died today. The Army is trying to determine whether it was soldiers or settlers -- both were present -- who fired the shots.

The 23-year-old woman's death and that of a 26-year-old Palestinian man -- who the Army said was shot and killed today when he attacked an Army officer -- brought the number of Palestinians killed by Israeli soldiers and civilians since the violence began Dec. 9 to 39 according to the Army and 43 according to U.N. figures. No Israeli has been killed in that time.

In addition, six Arabs were wounded by Army gunfire in incidents throughout the West Bank. The Army also announced it was extending indefinitely yesterday's school-closing order to all of the West Bank's 800 schools, sending 250,000 students home until further notice because it said the schools had become centers for organizing and stimulating new violence.

The stepped-up role of the settlers has fanned flames in this already volatile environment. This afternoon, a rumor spread through the Arab town of Tulkarm that settlers had kidnaped a boy and broken car windows. Soon dozens of demonstrators were in the streets, throwing stones at soldiers and burning tires, according to the Army. Soldiers fired tear gas to disperse the protesters, and a curfew was declared.

As their role grows, settlement leaders also have sought this week to undermine a new American diplomatic initiative in the region before it gets off the ground. They are warning that any attempt to grant political autonomy or other powers to Palestinians here will only encourage more unrest because it will be seen by Arab residents as resulting directly from the recent violence.

Cabinet ministers David Levy and Ariel Sharon, both potential challengers to Prime Minister Yitzhak Shamir as leader of the more hawkish Likud political bloc, have told settlement leaders they would oppose any peace plan that would freeze settlements or lead ultimately to an Israeli withdrawal from the West Bank and Gaza Strip.

Today Shamir, guarding his right political flank, added his support by appearing at a tree-planting ceremony in the West Bank settlement of Nili. Asked for his advice to the settlers, Shamir replied, "To be strong." And to Palestinians, he added, "To be quiet."

"Settlements will grow and prosper," Shamir told the crowd. Egyptian President Hosni Mubarak's call for a six-month freeze in settlements in return for a six-month halt in Palestinian protests was "not accepted by us," he said. "It belongs to the past. Without doubt there will not be any freeze on Israeli centers of population all over the country."

Geula Cohen, a legislator from the small, rightist Tehiya Party, whose constituency is largely from the settlements, warned the parliament that civil war would erupt among Jews if the government negotiated Israeli withdrawal.

"Judea, Samaria and Gaza are not Sinai," she said. "There shall be war; the war we shall wage will be first of all against the war being fought in this house . . . for our withdrawal from Judea and Samaria." Judea and Samaria are the biblical names for the West Bank.

Another settlement supporter, Yosef Shapira, a Cabinet minister without portfolio, confronted Defense Minister Yitzhak Rabin this morning and accused the Army of not doing enough to protect the settlers and warned they would form vigilante groups unless security was increased.

Rabin, a leader of the more dovish Labor Alignment, retorted that the settlers were "a burden" on the Army and should learn to keep quiet.

About 65,000 Jews live in 130 settlements in the West Bank, compared to 810,000 Arabs. Except for an incident three weeks ago when a settler leader shot and killed a 17-year-old Palestinian who allegedly had thrown stones, the settlers have kept a low profile during most of the first two months of conflict, relying on the Army to deal with the rioters.

But as young stone throwers attack more vehicles in an apparent effort to keep their cause alive, settlers are complaining that the Army is not doing enough. Three settlers and two soldiers were injured by stones here today.

Yosef Katz, a resident of the settlement of Efrat, whose car windows were smashed on the main Bethlehem highway today for the second time in three days, complained that "there were no soldiers in the area."

Joseph Seckbach, a Hebrew University biologist who lives in Efrat, said a group of youths no older than 10 or 12 rained stones on his car at the same spot this morning. His windshield and side windows were shattered and he had to have surgery to remove glass from his ear.

"The security was zero," said Seckbach, who said some settlers fired at the stone throwers, a report the Army did not confirm. "The Army ought to come with bulldozers like Ariel Sharon did in Gaza in 1970 and scrape away both sides of the road. Then it'll be quiet,"

Leaders of Gush Emunim, the main settler movement, have held a series of meetings since Monday to try to produce a strategy to deal with the violence and to get the Army to take a tougher stance.

Yehiel Leitner, a spokesman for the movement, denied any plans were afoot to organize vigilante committees. "We'd have to be idiots to do something like that," he said. "But we certainly would like to see a more determined effort by the Army and the government to quell this whole thing. People are worried. There's a lot of anxiety, and Yasser Arafat wants to hear that. But at the same time, that anxiety will not drive one person out of Judea and Samaria."

Others appear more willing to act on their own. The Interior Ministry reported a 50 percent increase in the number of people requesting permits for firearms in the past month, according to Israeli radio.

Cars filled with vigilantes have appeared on the main highway from the settlement of Beit El through the Arab town of Bireh, where the settler was firebombed on Monday. Similar groups could be seen today south of Bethlehem, near the Dehaishe refugee camp, a prime area of stone throwing. When youths stoned a commuter bus from Efrat this morning, passengers got out and threw the stones back.

Gideon Talmor, spokesman for the Egged bus company, said three buses were hit today, and 176 have come under attack since the clashes began.

"We feel we have become moving targets for these rocks," he said.