The fragile peace efforts launched a week ago at the Middle East summit in Aqaba, Jordan, appeared to be unraveling at a dizzying pace this week, as Israel and the Palestinians were drawn back into a familiar and bloody pattern of violence and retaliation.
In the latest day of violence, a suicide bomber dressed as a ultra-Orthodox Jew blew himself up on a bus in downtown Jerusalem on Wednesday, killing at least 16 people and wounding more than 100.
Israel's action following the bombing was swift: At least eight Palestinians were killed, including two senior Hamas members, in military helicopter strikes in the Gaza Strip on Wednesday evening. One of the men was identified as Massoud Titi, a senior leader of Hamas' military wing and the person Israel believes was behind the group's Kassam rocket firing. The other named was Suhil Abu Nahel, an aide to Hamas spiritual leader Sheik Ahmed Yassin.
Condemning the bus bombing, President Bush urged the parties to work to end the bloodshed. He also called on countries that want peace in the Middle East to fight terrorism and stop the flow of funds to groups like Hamas.
The suicide bombing and Israel's retaliation were the just the latest incidents in a bloody week. At least five Israelis were killed and five wounded in separate incidents in the Gaza Strip and West Bank on Sunday.
Israel responded to those attacks on Tuesday, when it launched a helicopter strike in Gaza City that wounded its intended target, senior Hamas official Abdel Aziz Rantissi, and killed two bystanders. Later Tuesday, Israeli helicopters attacked a residential era in the Gaza Strip, killing at least three Palestinians who had just fired rockets at an Israeli town, and wounding at least 30.
The strike on Rantissi, which prompted Bush to issue Israel a stiff rebuke, came a day after Prime Minister Ariel Sharon began fulfilling Israel's obligations under the "road map" peace plan, removing some 10 illegal outposts in the West Bank, most of them unpopulated.
Though the United States defines Hamas as a terrorist group, Bush criticized Israel's strike against Rantissi, saying it "does not contribute to the security of Israel."
Palestinian Authority officials also blasted the attack, but PA Prime Minister Mahmoud Abbas -- who called the strike an act of terrorism -- said it would not halt progress on the road map.
Israelis had been bracing for possible terrorist retaliation since the failed assassination attempt. Israel says Rantissi serves as the head of Hamas' military wing and believes he played a vital role in organizing Sunday's attack in the Gaza Strip that killed four Israeli soldiers.
The retaliatory attack against Israel was not long in coming. Wednesday's bombing occurred during rush hour, at around 5:30 p.m., as Egged bus No. 14A was making its way up Jerusalem's Jaffa Road toward King George Street. The bomber blew himself up as the bus was near a stop in front of a large office building not far from the Mahane Yehuda outdoor market.
"The bus was ripped apart by the force of the blast and heavy smoke billowed from it," area resident Roni Zada told the daily Yediot Achronot.
Reports said the bomber wore a kippah and tallit to pass as an ultra-Orthodox Jew.
Avraham Atrash, the Israeli Arab driver of the bus, was lightly wounded in the attack. He said he noticed nothing unusual about any of the passengers.
"Today I didn't see anyone suspicious," Yediot quoted him as saying. "If I did, I would have questioned them before letting them board."
Police said the bomb used in the attack was large and packed with nails and metal pieces to maximize casualties.
Jerusalem Police Chief Mickey Levy said a security alert had been in effect in Jerusalem, but there had been no concrete warning of such an attack.
Police Commissioner Shlomo Aharonishky said police anticipated that terrorist groups would try to carry out attacks when Israeli and Palestinian leaders were trying to engage in some form of dialogue. There were many terrorist warnings, Aharonishky said, playing down the depiction of Wednesday's bombing as a direct response to the assassination attempt on Rantissi.
But Hamas' military wing, which claimed responsibility for the bombing, said the attack was intended to avenge the strike on Rantissi.
Unfazed by international criticism of the assassination attempt, Sharon said Israel would not compromise its fight against terrorism.
"Israel will pursue to the end Palestinian terrorist organizations and their leaders, [including] those who initiate, finance and dispatch terrorists," Sharon said Wednesday evening. "We have a deep commitment to make every effort to advance a political process that will bring we hope peace and quiet. We will take every step to protect the security of Israeli citizens."
In remarks to cabinet ministers before the Jerusalem bombing, Sharon was quoted as saying that Israel had made clear its position on fighting terrorism to the United States and the Palestinian Authority.
Israeli officials have acknowledged that Abbas must be given an opportunity to establish himself, but Israel justifies its anti-terror actions by charging that the Palestinian Authority is not taking necessary anti-terror actions.
Several PA officials voiced responses to the attack. Abbas urged Israel and the Palestinians to work toward implementing the road map.
In unusually explicit language, PA President Yasser Arafat condemned the "terrorist attack in Jerusalem," while also denouncing as terrorism Israel's attack on Rantissi.
Other PA officials blamed Israel for the recent escalation, accusing the Sharon government of deliberately sabotaging peace efforts.