TEL AVIV, Oct. 15 (JTA) — Any doubts about the close link between the war on terrorism and the Israeli-Palestinian conflict have gone the way of a U.S. jeep loaded with diplomats on a dusty Gaza highway. There was no immediate claim of responsibility for Wednesday´s roadside bombing, which killed three American security agents and wounded a junior official from the U.S. Embassy in Tel Aviv. But it had all the hallmarks of Palestinian terrorist attacks against Israeli vehicles, and it set a new precedent for Palestinian violence. President Bush blamed the Palestinian Authority for not cracking down on terrorist groups, despite numerous pledges to do so. "Palestinian authorities should have acted long ago to fight terror in all its forms," Bush said in a written statement Wednesday. Their failure to do so, he said, "continues to cost lives." An unwillingness to reform P.A. security forces and dismantle terrorist groups "constitutes the greatest obstacle to achieving the Palestinian people´s dream of statehood," Bush said, blaming P.A. President Yasser Arafat for hindering reforms. The dead Americans were identified as John Branchizio, 37, of Texas; Mark Parson, 31, of New York; and John Martin Linde, 30, of Missouri. The three were on contract to the U.S. Embassy in Tel Aviv through the defense contracting company Dyncorp, State Department Spokesman Richard Boucher said. U.S. officials expressed outrage at the bombing. In a phone call with P.A. Prime Minister Ahmed Karia, U.S. Secretary of State Colin Powell said the Palestinians could not move toward statehood "without eliminating violence and terrorism." FBI investigators are being dispatched to the region, U.S. Ambassador Daniel Kurtzer told reporters in Tel Aviv. The Israeli army sent tanks and armored vehicles, under cover of a helicopter gunship, to help the Americans evacuate the wounded man and the bodies of the victims. Embassy officials who arrived on the scene to document the wreckage had barely managed to pull out their cameras when they were attacked by stone-throwing youths from the nearby Jabalya refugee camp. The Americans beat a hasty retreat as Palestinian police fired in the air to disperse the crowd. Kurtzer´s cultural attache was in the convoy, which was on its way to meet with Palestinian candidates for Fulbright scholarships to U.S. universities. "It remains to be seen" if the program will be suspended in Palestinian areas, Kurtzer said. According to Palestinian sources, Fulbright alumni in Gaza had been instructed not talk to the press as a probe began. That was an indication that authorities were covering all angles of an ambush that clearly targeted U.S. diplomats, a first for this round of Israeli-Palestinian conflict. Arafat called the bombing an "ugly crime" and pledged to find the culprits. So did Karia. Analysts did not expect the attack to affect U.S. commitment to the "road map" peace plan. But, they said, if the Palestinians fails to find the culprits, it could erode any remaining U.S. confidence in P.A. anti-terror efforts. Palestinian terrorist groups sought to distance themselves from the attack. "We view it as inappropriate to target Europeans, Americans or any nationality other than the occupation forces" of Israel, an Islamic Jihad leader, Nafez Azzam, told Reuters. While Washington weighed its options, Israeli officials made clear that they do not consider this a random act of bloodshed but, if anything, a blood bond between two old allies. "It´s not just because of U.S. support for Israel as such, but it is because of what Israel and the United States both together stand for," Sharon adviser Ra´anan Gissin said of the motives for the attack. "They stand for life, for liberty, for democracy here, for pursuing peace," he said. "These victims are victims because of the gallant and very courageous policies that President Bush has been carrying to try and promote peace and hope to the people of the Middle East."