JERUSALEM, OCT. 31 -- On a day of stunned anger and pain, Israel buried a young Jewish mother and her three small sons this afternoon and began taking vengeance on the West Bank town of Jericho for last night's Arab firebomb attack on the bus in which they were riding.

The day began with a predawn Army sweep through the ancient Arab town that rounded up 150 young male suspects and resulted in the arrests of seven men, three of whom later confessed to the attack, according to Army officials. Their three houses were demolished this afternoon, as were hundreds of orange, banana and date trees in the field where the assailants had lain in wait for the regularly scheduled civilian bus.

It ended with a simple but anguished ceremony at the old Jewish cemetery atop the Mount of Olives. The four charred bodies -- Rachel Weiss, 26, in a white shroud and her three sons, Netanel, 3, Rafael, 2, and Efraim, 10 months, together in an open pine coffin -- were interred in a small hole scratched out of the hard rock on a barren hillside.

Analysts, meanwhile, weighed the consequences of the assault on Israel's closely contested national election, which takes place Tuesday. Their consensus: an angry backlash among voters is likely to boost the electoral prospects of Prime Minister Yitzhak Shamir and his right-of-center Likud party, which has pledged to take a tougher approach against the 11-month-long Arab uprising in the occupied West Bank and Gaza Strip.

Pollster Elihu Katz said the killings would likely bring to the polls Israelis who had not planned to vote but who have right-wing leanings. He predicted that they could give the right up to two more parliamentary seats in its race against Foreign Minister Shimon Peres' more dovish Labor Party.

"It's tiny numbers, but tiny numbers may make the difference in this election," Katz said.

Defense Minister Yitzhak Rabin said the attack, the bloodiest against Israeli civilians since the uprising began, was so onerous that he would ask Army prosecutors to seek the death penalty for those responsible. In its 40-year history, the Israeli state has executed only one person, Nazi war criminal Adolf Eichmann. The hard-line response by Rabin, a Labor Party leader, was interpreted by some as an attempt to thwart any shift in voter sentiment toward Likud.

Rabin also announced that the Army is sealing off the West Bank and Gaza for two days beginning late tonight to prevent disruptions of the Israeli elections. Palestinians from the occupied territories will not be allowed into Israel and journalists will be allowed into the territories only with an Army escort, officials said.

The assault came just two weeks after a car-bomb attack that killed eight Israeli soldiers in southern Lebanon. But in many ways, the bus attack is even more devastating to the Jewish state's psyche and sense of security because it was directed against civilians and took place not in perceived enemy territory but on a generally quiet highway that is the main north-south car route for Jerusalemites and thousands of others living in Israel's interior.

Rabin and senior military officials who toured the site early this morning told reporters the attack was carried out by at least three local residents, all from the same clan, two of whom had been arrested before but none of whom was affiliated with any Palestinian nationalist group. They reportedly discussed the idea over the course of a few days and settled on a target while playing cards at a local cafe two nights ago.

They chose a spot on the northern outskirts of the town where the road bends and vehicles must slow. Officials said dozens of other molotov cocktail attacks had occurred there in recent months.

The three assailants waited while an Army jeep passed by the site, then attacked Egged passenger line Bus 961, which came by one minute later. "There is no doubt the murderers meant to attack civilians," Rabin said.

Most of the 22 passengers jumped off the bus unharmed, including Rachel Weiss' husband Eliezer. But Mrs. Weiss and her three sons were in the rear where the children were asleep and where at least one of the gasoline bombs landed through an open window.

According to witnesses today, Mrs. Weiss appeared to panic, fearing the bus was under attack from terrorists who would shoot her and her children if they got out. She fought off a young soldier who tried to pull her and the baby she was holding off the flaming vehicle. He finally had to flee from the thick smoke and flames, leaving her alone with the children.

Jericho remained under military curfew tonight and Rabin told reporters it would stay closed until all of the perpetrators and their helpers had been caught. Military officials said Jericho residents would have to learn they could not allow such attacks to take place in their town.

"In this process of looking for other cell members, the population of Jericho will also suffer and we are sorry about that," said Gen. Dan Shomron, Army chief of staff.

The attack undermined recent efforts by Palestine Liberation Organization leaders to encourage voters to back Israel's "peace camp" -- parties ranging from the mainstream Labor to the far-left Communists. The PLO's office in Cairo, tacitly acknowledging the damage done, condemned "any killing of civilians from any side," and added, "The incident yesterday emphasizes the need for peace."

A group of prominent Palestinian moderates in the territories who support the PLO also deplored the violence, saying "attacks on both sides show the need for a just peace based on both peoples' right to self-determination and their own state."

But some analysts said the moderate Palestinian language would be viewed by many Jewish Israelis with great suspicion. Some cited recent efforts by Palestinian gunmen to infiltrate into northern Israel from Lebanon and last week's arrest of 13 Palestinians in West Germany for weapons offenses as evidence that the PLO is playing a double game -- talking peace while waging war.

"Israelis get so tired and their nerves get so stretched that they become much more susceptible to strong, simplistic solutions," said Jewish philosopher David Hartman. "So you go and cast your ballot for Shamir not for ideological reasons but because you are psychologically worn out and and you vote for the one who can respond to that deep feeling.

"People are also feeling that they don't trust anybody and any form of compromise is interpreted by the other side as weakness -- and that Peres with his suggestions of territorial compromise and an international peace conference is inviting these kinds of attacks."

Hundreds of mourners crowded the narrow streets of the dilapidated Shaare Hesed neighborhood where Rachel Weiss was raised as one of 18 children by a father who came from Germany and a mother who was a ninth-generation Jerusalemite.

Her father, Rabbi Shlomo Zilberman, stood in the street outside his house surrounded by people weeping. He cried repeatedly in a singsong voice, "She was my pretty child; she had such dear children."

Mourners followed on foot as two blue vans transported the bodies across central Jerusalem to the Mount of Olives, where Jewish tradition claims the Messiah will stop first to raise the dead on the day of resurrection.

Tradition says the bodies should be buried before sunset, so the ceremony at the cemetery was brief. A dozen women stood at a distance while about 200 men in black coats and long earlocks pressed against each other, struggling to remain on their feet as they tried to hurry the shrouded corpse and the small, open coffin into the bleak gravesite.

Just as the sun began to dip below the Old City's walls in the distance, Rachel Weiss' sobbing husband shoveled the first scoop of dirt into the hole. Soon it was filled and the long day was over.