KIRYAT ARBA, FEB. 9 -- They set out early each morning after prayers in groups of three or four per car. Some roam the north along the highway to Ramallah and Nablus, others the south from Hebron to Jerusalem. They carry automatic rifles, handguns and billy clubs -- weapons they appear increasingly prepared to use.

In recent days Jewish vigilantes have started patrolling the winding, rock-strewn highways of the Israeli-occupied West Bank. Their purpose, they contend, is to be a supplemental security force to provide some of the protection that what they see as an overstretched and politically hamstrung Army cannot deliver.

But the Army says that although the groups are only a small proportion of Jewish settlers, they have sown panic in Palestinian towns in the West Bank. The result has been fresh violence in villages that until now had been relatively untouched by the two-month-long wave of civil violence that has claimed at least 50 Arab lives in the West Bank and Gaza Strip.

The patrols began last week and were portrayed as an attempt to let off steam by Jewish settlers angered by the firebombing of a settler's car in Bireh and by the stoning of dozens of other cars and buses, including vehicles that take several thousand children to school. Senior Army officers held meetings and preached restraint, but said they would not interfere so long as the patrols remained nonviolent.

But the game soon turned deadly. After settlers rampaged through one West Bank village smashing car windows, Palestinians in several other communities panicked, Army officials said, and blocked roads, burned tires and stoned soldiers who came to disperse them. One villager was killed in Tulkarm, one in Ayub, and three in Beit Ummar on Sunday morning, all after rumors of settler incursions that the Army says never took place.

Yesterday morning the violence moved to Qaddum, a remote village west of Nablus. Residents said two Jewish settlers they recognized from nearby Kedumim drove up in a van. When some villagers sought to block the road and allegedly threw stones, the driver got out, fired a machine gun and hit one man twice in the head. He died at a Nablus hospital.

The man who allegedly fired the shots is in custody being investigated by police, authorities said, and senior Army officers have repeated earlier warnings that law enforcement is not the job of the settlers.

"This is a job for the Army," Maj. Gen. Amram Mitzna, commander of the West Bank, told a gathering of settlers earlier this week. "If there are any people who don't think so, I say that taking the law into your own hands is very, very dangerous. It is the beginning of anarchy."

But the vigilantes do not see it that way. To them, the uprising in the territories is a test of their will to survive and rule, and producing panic among the Arabs is exactly what they have in mind.

"It's good that the Arabs feel that way about us," said Shmuel Ben Yishai, a spokesman for the vigilantes who lives in this Jewish enclave outside Hebron. "They are not afraid of the soldiers but they are afraid of us. They have experience with us."

Ben Yishai and a small group of right-wing activists, members of Rabbi Meir Kahane's anti-Arab Kach party, a year ago set up a vigilante group they call the Committee for Safe Traveling. It sputtered along all last year with patrols by 20 to 30 people of the main highways and Palestinian refugee camps. Now, says Ben Yishai, there are up to 100 participants.

Three other "self-defense committees" have also been formed in Kiryat Arba by separate groups whose politics are less extreme than Kahane's.

Sometimes they do more than merely patrol. Some have set up roadblocks to search and sometimes harass Arab vehicles. On Sunday morning, Arab residents in Hebron woke to find the windshields smashed and tires slashed on dozens of parked cars.

"We knew who it was," said a fruit vendor in Hebron yesterday. "They made no effort to hide."

Ben Yishai, 29, is an electrician with four children, who packs a pistol at all times and whose crowded apartment here has become the command center for the vigilantes. He was called in for police questioning Sunday night but denied any knowledge of the vandalism.

"It's very sad because the right answer for breaking the head of a Jew is not breaking the glass of a car," he says. "I'm not against breaking car windows but it's not the answer.

"The Jewish nation does not learn very fast. The stones are helping people understand that we have a war here between two nations and you can't buy the Arabs' pride with good housing or cars or jobs. We have a cancer here in this country and the way you deal with a cancer is either you cut it out or you die."

To the rest of the world, Defense Minister Yitzhak Rabin and his "break-their-bones" policy sound hard-line. To Ben Yishai it sounds weak. When Rabin denounced the vigilantes today as causing "destructive results," Ben Yishai laughed derisively.

"Rabin cares about my kids like I care about snow in the Alps," he said. "If one of my kids gets killed, Rabin would say it wouldn't have happened if we didn't live here. I don't want him to put a flower on my grave. I want to live."

The Kahane supporters, who advocate the forced expulsion of Arabs from both the occupied territories and Israel proper, are to the right of the main settler movement symbolized by the Gush Emunim organization. That group's members contend coexistence with Arabs is possible so long as the Arabs recognize that the West Bank -- which Israeli Jews call Judea and Samaria -- rightfully belongs under Jewish rule.

The Gush leadership says it has no use for the vigilantes because they are inadvertently uniting Arabs against Jews. The vigilantes "are a small minority," says Gush Emunim ideologist Elyakim Haetzni, a lawyer who also lives in Kiryat Arba. "They're making a grave mistake because they are helping Yasser Arafat to make some small riots into a general uprising."

But critics contend that some of Gush Emunim's own statements further the cause of the vigilantes. After a settler was seriously injured by stone throwers last week, Gush spokesman Noam Arnon suggested that the village from which the rioters came, Kfar Malik, be leveled.