JERUSALEM - On a day punctuated by a series of deadly attacks across Israel and the West Bank, an explosion probably triggered by a Palestinian suicide bomber ripped apart a bus full of Israeli soldiers in northern Israel yesterday morning, killing at least nine people.

Dozens of people were killed or wounded in the violence yesterday, one of the most violent days in months.

About 3 1/2 hours after the bus blast, a Palestinian armed with two pistols shot and killed an Israeli telephone worker outside Jerusalem's walled Old City, prompting a gunbattle with police that left the gunman and a bystander dead and 17 others wounded.

Later in the afternoon, a roadside bomb damaged a car, and Palestinian gunmen opened fire on a bus in separate incidents near Jewish settlements in the West Bank. Seven Israelis were injured in the two incidents, several of them seriously.

In the Gaza Strip, soldiers fatally shot an armed Palestinian in a wet suit who had swum to an area near the Dugit and Alei Sinai Jewish settlements, army officials said.

And early today, an Israeli mother and father were killed, and their two children, 6 months and 3 years old, were injured when Palestinians shot at their car in the northern West Bank near the Jewish settlement of Ariel.

Also today, Israeli troops fatally shot two Palestinians, including a fugitive local leader of Yasser Arafat's Fatah movement, in the village of Borqa, north of Nablus, relatives said.

Israeli police said they strongly believed that a suicide bomber from Jenin was responsible for the bus explosion near the town of Tsfat, which would bring the death toll to 10.

But they also were investigating the possibility that the bomb had been planted. They were searching for two young Arab women who had gotten off just before the blast.

The militant Islamic Resistance Movement, or Hamas, claimed responsibility for blowing up the bus and said it was part of its revenge for a July 23 Israeli airstrike, which killed one of its leaders in Gaza and 14 bystanders. The group described it as a "martyr attack," indicating it was most likely a suicide operation.

The blast was four days after a Hamas militant triggered a bomb that blew apart a cafeteria on Jerusalem's Hebrew University campus, killing seven people, including five Americans. The group said that also was a retaliatory strike for the Gaza strike.

Aqsa Martyrs Brigades, an offshoot of Arafat's Fatah faction, claimed responsibility for the shooting and subsequent attacks yesterday on Israeli vehicles in the West Bank.

Meanwhile, Israeli officials are desperately trying to find new ways to combat the latest surge in violence with a two-pronged approach of strong military assaults on Palestinian cities, such as the push into the center of Nablus over the weekend, and deterring attackers by expelling their relatives and demolishing their homes.

Israeli Prime Minister Ariel Sharon and Defense Minister Benjamin Ben-Eliezer canceled meetings they had scheduled today with top Palestinian officials to discuss security and a possible withdrawal of troops from at least one West Bank city. Those meetings might happen later this week.

But Sharon said he would continue to ease restrictions on Palestinians in the West Bank, where 700,000 people have been under occupation by the Israeli army for seven weeks, by extending curfew breaks and issuing more permits to allow workers into Israel.

And a Palestinian Authority delegation is set to meet in Washington this week with Secretary of State Colin L. Powell to discuss security reforms. It would be the highest-level talks between the two groups since President Bush suggested that restoring order would be easier without Palestinian leader Arafat.

Bush condemned yesterday's violence.

"There are a few killers who want to stop the peace process that we have started," an angry Bush said from Maine, where he is vacationing. "We must not let them. For the sake of humanity, for the sake of the Palestinians who suffer, for the sake of the Israelis who are under attack, we must stop the terror."

The Palestinian Authority condemned the bombing, too, but blamed the violence on Israel's military operations in the West Bank, its invasion of Nablus on Friday and curfews it has imposed on seven Palestinian cities.

The bus was bombed about 8:45 a.m. on the first day of the Israeli workweek as it traveled from the northern port city of Haifa to stops in the north, several miles from Lebanon's border.

As is typical on a Sunday, the bus was filled with Israeli soldiers heading to their bases after weekend leave. The bomb went off as the bus approached a stop at the Meron Junction, about five miles west of Tsfat.

The explosion, near the center of the green Egged bus, caved in the metal frame, dented the roof, and crumpled and twisted the back. Witnesses described a deafening blast followed by a fireball that sent pieces of bodies more than 100 yards.

Dry brush burned for hours along the roadside as rescue workers treated the more than 40 injured and cleaned up the carnage. The stench of burning metal and flesh turned a searing day acrid; shoes, wallets, jewelry and a child's drawing were scattered in the debris.

"I picked up four dead myself," Haim Ben-Shimon, told Israeli Radio. "The bus is simply crushed." Another witness, Pinkas Cohen, told the radio station that "the entire rear end of the bus was blown off. A soldier came out with his face and uniform covered with blood."

Many of the dead and wounded were soldiers, police said. Six victims were identified last night; all were in their early 20s. Three were soldiers.

About 50 people from a Baltimore synagogue on a two-week solidarity tour were in northern Israel yesterday. They are scheduled to go to Tsfat and to a tomb near the blast site.

Rabbi Moshe Hauer, who is leading the group from the Bnai Jacob Shaarei Zion congregation on Park Heights Avenue, said people are wary. "But it's not a paralyzing fear," he said shortly after learning of the bus attack. "We are here for a reason, and we are going about what we came to do. It's been a memorable experience."

Israeli television was broadcasting live from the bombing scene when news of the shooting in Jerusalem broke. Shortly before noon, police said, a Palestinian man accosted the Israeli driver of a Bezeq telephone communications truck that had just come out of the Old City.

The gunman wounded the driver, then walked around to the passenger door, pulled out a security guard and fatally shot him. A border police officer rushed over and fired back with a machine gun.

A gunbattle raged for about 20 seconds, and two bursts of automatic weapons fire could be heard a mile away in downtown Jerusalem, startling pedestrians. Witnesses said bullets flew in virtually every direction near the al-Umal cafe, which means hope in Arabic.

The cafe is near the main road outside the Damascus Gate, an often volatile and crowded entrance to the Muslim Quarter of the Old City.

When the shooting subsided, the 19-year-old gunman lay dead under the cafe's awning in front of a falafel stand. The body of the 32-year-old telephone company security guard lay across a small plaza, under the running board of the truck. A third man, a 51-year-old Palestinian from East Jerusalem, was killed as he ate lunch at a table inside the cafe. Seventeen others were injured, including several police officers.

Jerusalem Police Chief Mickey Levy said his officers accidentally killed the bystander inside the cafe. "When there are exchanges of fire between Palestinian terrorists and police officers in a crowded area, it is very likely that innocent bystanders will be wounded," he said.

At least six Palestinians from East Jerusalem were among the wounded; most of their injuries were from shrapnel. One man was on the verge of passing out when Israeli medics rushed to him, ripped open his shirt and found his chest peppered with shrapnel.

"I heard the shooting, and I ran," the man told a medic in Arabic. "Suddenly, I felt a pain in my chest." A woman sat near him, crying as she cradled a small child, and was rushed to a hospital to be checked. Another man was carried away, face down on a stretcher, his hands cuffed behind him.

Carl Williams, 33, a tourist from Boston on his second day in Israel, was outside a nearby cafe when he saw the gunman. When the shots rang out, Williams and his twin brother, Chris, both computer programmers, hit the ground and crawled into a shop for safety. "I wanted to see what was happening here," he said of his reason for visiting Israel. "This is what happens when people have no hope."

Israeli police said the shooter came from Hebron, which is south of Jerusalem and one of the cities that has remained relatively quiet. It has been mentioned as a test case for an Israeli army withdrawal.

Israeli leaders met with army commanders yesterday afternoon to discuss a possible response to the latest round of violence, which comes despite the army's presence throughout the West Bank. After the Hebrew University bombing, troops around Nablus moved into the covered marketplace.

Troops had fought a days-long battle there in April, killing dozens of Palestinians, but had not been back since. Despite the occupation, they had stayed out of the market, and they said Palestinian militants had turned the small shops into a new stronghold.

The army moved in on Friday and began house-to-house searches. Spokesmen said yesterday that they had uncovered four bomb laboratories with explosives, small missiles, grenades, guns, stockpiled ammunition, flak jackets, fertilizer, detonators and instructions on how to carry out attacks.

Ben-Eliezer said the army had confiscated so many explosives that "there are more suicide bombers than bombs" in the West Bank. He said 10 potential suicide bombers had been arrested or killed in the past several days, and he warned that more attacks are possible.

Military officials said this operation in Nablus is different than the one in April, which concentrated on the Aqsa Martyrs Brigades. This time, they said, they are going after Hamas bombers and planners in one of the first direct strikes against the militant group, whose leaders are in Gaza.

Such a group is difficult to go after because it has no infrastructure and works out of homes and mosques. Even assassinating their leaders, as happened last month, poses significant risks to bystanders, which Israel discovered last month in Gaza.

The army also pressed ahead with its renewed campaign to demolish the houses of Palestinian attackers. In the past two days, armored bulldozers have destroyed nine dwellings in Jenin, Nablus and Hebron.

And yesterday, a military appeals court continued to hear evidence in Israel's latest bid to deter attacks by expelling relatives of bombers to the Gaza Strip.

The Israeli attorney general supports the move, but only against relatives proved to have knowledge beforehand of an attack or proved to have helped carry it out. Otherwise, the official has warned, the move would be considered collective punishment and might violate international law.

The military court remained undecided yesterday and is scheduled to reconvene today.

The Associated Press contributed to this article.