TULKARM, WEST BANK -- Palestinian children scattered up narrow alleys and their elders watched in sullen silence as Col. Jonathan (Yoni) Shimshoni drove by in his Israeli Army jeep, accelerating to make a fleeting target for teen-age stone throwers.

For Shimshoni's artillery brigade, Tulkarm's civilians have become a new kind of enemy, an unfamiliar foe to be fought with billy clubs and tear-gas grenades instead of howitzers. The assignment, to help put down a 10-week-old Palestinian uprising in Gaza and the West Bank, has proved more difficult and uncomfortable than the Israeli military anticipated, and Shimshoni's unit is paying the consequences in this region of the West Bank.

In Tulkarm, and nearby Qalqilyah, the other main town in Shimshoni's sector, as well as throughout the occupied territories, Palestinian youths and their families have persisted far beyond Israeli authorities' expectations in violent demonstrations and a commercial shutdown to dramatize frustration with two decades of military occupation.

The length and extent of the campaign have opened an unwelcome horizon for the Israeli Army: long-term patrolling to suppress unruly Palestinian nationalists by soldiers trained to combat Arab armies.

"At first we thought we were going to end the violence, to turn the pages back the way they were," Shimshoni said. "Now I think we've caught on that we're not going to do that. Things are going to be different."

Although Israeli authorities acknowledge that their crackdown has been severe, they have contested numerous reports of widespread brutality during the Palestinian uprising. The Israeli Army denied repeated requests over a two-week period to spend several days and nights with the soldiers, but arranged a day with Shimshoni's brigade.

Israel's occupation of Gaza and the West Bank has been based on force and fear since the territories were captured in 1967 from Egypt and Jordan. But police, paramilitary border units and the Shin Bet intelligence apparatus, backed by small Army contingents, had been sufficient to enforce Israeli authority until the unrest exploded in early December.

Since then, because of the large number of Palestinians involved and the spread of violence across the contested areas, the 100,000-man Army has been called in on a large scale as the only organization with enough weaponry and manpower to suppress the Palestinian challenge.

Officials have declined to divulge the number of soldiers deployed against civilians. But the streets and roads of Gaza and the West Bank have been blanketed with military vehicles and foot patrols. Deputy Chief of Staff Ehud Barak said Wednesday that the increased responsibilities likely will mean extending the annual tour of duty for some of Israel's half-million reservists.

Shai Stein, a civilian who fought in Israeli wars as a lieutenant colonel in a paratroop brigade, said the current crisis has created new and ugly tasks for Israeli soldiers. The warfare that Israel's Army has known in the past involved mostly conflicts with modern weapons fired from a distance, he explained, but now young soldiers are being ordered to control and club civilians at close range.

Shakha, a sergeant leading a six-man platoon up and down the main road through Anabta near here, has learned the hard way what the change in duty means. Trained as a medic in Shimshoni's artillery brigade, he has been issued a wooden club instead of bandages and ordered to prevent youths from throwing rocks at passing cars instead of tending to wounded soldiers on the battlefield.

"The women get up on the roof and they shout at the boys down on the street, who then throw stones," he explained to a visitor asking what he does. "Then when we come and try to catch the boys, the women shout again and the boys run away."

The Israeli Army, aided by Shin Bet informants, has acquired a vast amount of information on the new enemy. In Shimshoni's headquarters, for example, giant aerial photographs have been hung on the wall to show every street and building in Tulkarm, its adjacent refugee camp and Qalqilyah.

Each building has received a number, carefully noted on the photographs. When a patrol reports a stone or molotov cocktail has been thrown, Shimshoni can know instantly who lives behind the wall it came from.

But for all the information, Shakha's men seemed starkly foreign in the village of Anabta as they marched back and forth one recent afternoon. Although he was raised in Israel, for instance, Shakha expressed amusement at Palestinian women who walked down the street in traditional dresses and scarves covering their hair according to Moslem stricture.

"The women here are fat, and they wear those dresses," he said, apparently measuring what he saw by the largely western dress of Israeli women. "And you can't see their faces."

The platoon passed repeatedly in front of a Palestinian home where middle-aged men, dressed in gray suitcoats or robes topped by checkered headdresses, sat in the courtyard talking quietly. Some looked up at the passing Israelis, but most averted their glance.

"There in that house they are having a funeral," Shakha said. "They are praying to God, or I don't know what they do. But they know that if they are quiet, we do nothing to them. We do nothing to them, and they do nothing to us."

Since the uprising began, however, thousands of Palestinians have not been quiet, and thousands of Israeli soldiers have done a lot to quell them. More than 60 Palestinian civilians have been killed and hundreds more have been severely beaten.

A 21-year-old soldier who called himself Jonathan expressed dismay at what has happened. He said he returned from leave to find his Army friends recounting with pride and amusement the beatings they had meted out to Palestinians.

"The animal in them comes out," he said. "They talk about it as if they are proud of it. I don't recognize some of my friends any more."

An Army escort officer, assigned to monitor a visiting reporter, told Jonathan he should talk only about what he has actually done or seen. When Jonathan persisted, the officer suggested the reporter should talk to someone else. The two were seen later exchanging words.

The chief Army psychologist, Col. Shlomo Dover, said Tuesday that 70 percent of Israeli soldiers contacted in a survey felt Army actions they saw or carried out were fair to Palestinians. Shimshoni said most members of his brigade, despite some distaste for their assignment, like being involved with what is going on.

"It gives them a sense of being in on a historical process, and of being on the front lines of the historical process," said Shimshoni, who holds a PhD degree from Princeton University. "When they first come in, there is a novelty. That novelty wears off as time goes by, but the sense of being at the center of the action remains."

Shimshoni said that at the beginning it was difficult to get soldiers to put down rioters with clubs because their training did not take them in that direction. But by now, he said, most consider it a job that must be done.

"If you had shown a movie four months ago of what the Israeli Army has been doing, people would not have believed it," he said.