Israeli officials said the shootings were proof positive that the Palestinians were no longer engaged in an intifadah, or uprising, but had launched a guerrilla war.
"It is now beyond a shadow of a doubt that we're talking about a guerrilla war," Israeli government spokesman Moshe Fogel said last night. "They are trying to turn the West Bank into Lebanon."
In response, Israel reimposed a strict closure on the West Bank and Gaza, forbidding Palestinians not only from entering Israel but even from traveling between Palestinian towns. It is unclear what harsher measures might await after Israeli Prime Minister Ehud Barak returns today from a trip to the United States.
Israel believes the attacks are being conducted by plainclothes Palestinian police and militias loyal to Fatah, the political organization of Palestinian leader Yasir Arafat.
"The gunfire and ambushes have become a repeated pattern of Palestinian terror in these days, and they enjoy the support of the Palestinian leadership," Maj. Gen. Yitzhak Eitan, a senior Israeli army official, said at a news briefing late last night. "They want to kill as many Israeli civilians as possible."
The Palestinians did not entirely dispute the assertion.
Ziyad Abu Ain, an aide to West Bank Fatah leader Marwan Barghouti, told Israeli reporters yesterday: "This is the price of the Israeli war against the Palestinians. "
The Palestinians are directing their fire at Israeli soldiers and Jewish settlers in the West Bank and Gaza. The first attacks yesterday took place near Ofra, a West Bank settlement five miles northeast of Ramallah, on a road used by Palestinians and by Jewish settlers.
It came around 4:15 p.m., when Palestinian gunmen in a white Fiat Uno raced past an Israeli civilian car and fired. A 41-year-old schoolteacher, Sarah Lisha, was killed. Lisha was the mother of five and lived in the nearby settlement of Neve Tsuf.
A few minutes later, the same assailants fired on a shuttle bus carrying Israeli soldiers. Two 18-year-old soldiers, identified as Elad Valenstein of Akshelon and Amit Zanah of Netanya, were killed.
In the evening, the violence moved down to the Gaza Strip. About 8:15, Palestinian gunmen opened fire on an Israeli convoy passing the Kfar Darom junction. A truck driver was killed. His name had not been released last night.
There were no reports that the Palestinian assailants were captured.
The shootings will increase the pressure on Barak to take even stiffer measures against the Palestinians. In the last week, Israeli attack helicopters have killed three Palestinian Fatah activists in retaliation, but the Israeli right remains sharply critical that the army has not used its full firepower to quash the uprising.
"Those who were killed in the attack were the victims of the policy of restraint which Barak has imposed on the army," the lobbying organization of Israeli settlers said yesterday in a statement after the shootings.
Barak met Sunday night with President Clinton in Washington in yet another last-ditch effort to rescue the peace negotiations. He was due to speak last night to American Jewish leaders in Chicago.
Meanwhile, there are few signs that the Palestinians will accede to Israel's pleas for peace or threats of retaliation. In Doha, Qatar, Arafat held a rare meeting with Khaled Mashal, a leader of the militant Islamic group Hamas, to discuss unifying the Palestinian position.
On the West Bank, Fatah distributed a pamphlet calling for Palestinians to intensify resistance to Israel in the coming days in honor of the anniversary tomorrow of the Palestinians' first declaration of independence in 1988 at a conference in Algiers.
Barbara Demick's e-mail address is email@example.com