AMMAN, Jordan, March 4 — Arabs reacted with optimism and unease to the speech by President Bush today, welcoming direct American involvement in attempts to end the Israeli-Palestinian conflict while worrying that the president may fail to halt the hounding of Yasir Arafat.

Arab leaders have demanded all week that the Bush administration rein in the Israeli tanks rolling through the occupied territories and dispatch a more senior envoy than retired Gen. Anthony C. Zinni to mediate in the conflict. So the president's announcement that Secretary of State Colin L. Powell would travel to the region was welcomed.

"People were getting desperate," said Mohammed Benaissa, the foreign minister of Morocco, speaking by telephone from there. "If America doesn't do it, nobody else can do it," he added. "Sending the secretary of state is a very strong signal."

Although Mr. Bush demanded that Israel halt its operations on the West Bank and insisted that the two sides find their way back to the negotiating table, there was concern that Mr. Bush associated Mr. Arafat so emphatically with terrorism and accused him of being the author of his own predicament.

"There are a number of issues that we can support," said Hesham Youssef, the spokesman for the Arab League in Cairo. He cited the president's call for two adjacent states living peacefully, for an end to Israeli settlement activity, and for an end to the daily Israeli humiliations of the Palestinians.

"But there are a number of things we cannot share with the United States, including viewing the world through the prism of terrorism," Mr. Youssef noted, saying that concern stemmed less from the speech than from the Bush administration's foreign policy since Sept. 11, which has made the fight against terrorism its chief focus. Some leaders, including Palestinians, have argued that not every armed struggle for statehood can be classified as terrorism.

Many Arab diplomats and analysts were also concerned that Mr. Bush did not call for an immediate halt to Israeli military activity, leaving open the possibility that Israel could prolong its incursion at least until next week, when Secretary Powell is scheduled to arrive.

"We want to see progress on the ground," Mr. Youssef said. "We want to see an end to the siege on Arafat, and more importantly on the Palestinian people."

Many in the Arab world expected a test of wills to develop between Prime Minister Ariel Sharon of Israel and the American administration over the timetable of a cease-fire.

Mr. Bush's statement that Mr. Arafat's failure to control suicide bombers landed him in his current predicament left many Arab officials feeling that the president had left the door open for Israel to kill or exile the Palestinian leader.

Several Arab diplomats called it a "dangerous" speech because Mr. Bush left the impression that the Palestinians might do better with another leader.

There was no official reaction from Damascus, where there was a massive state-directed demonstration against Israel today. But even though Mr. Bush again singled out Syria for criticism, suggesting it had to decide whether to support peace or violent groups like Hamas, Syrians found some change in the American position.

"It is a more positive attempt, not extremely positive, but a more positive attempt to put an end to the deteriorating situation in the Middle East, which threatens to endanger American interests," said Imad Fawzi Shueibi, a political science professor at Damascus University.

He said it was likely that Washington realized that trying to achieve anything in the Middle East would be thwarted by the bloodshed in the occupied territories.

"It is time for a more serious peace process now that America found itself losing all the support it had gathered for its antiterror campaign and for its war against Iraq," Prof. Shueibi said. "On both fronts, it has lost the support of the Arabs because of its support for Sharon."

Europe
Shift is Welcomed as `Very Significant'
President Bush's statement on the Middle East was received favorably tonight in Europe, where sentiment has been running high that the United States must put pressure on Israel to curb military actions against the Palestinians and to end Mr. Arafat's isolation.

In London, a Foreign Office minister, Ben Bradshaw, said the government viewed Mr. Bush's speech as "a very, very significant shift" and hoped it would "sink in" with the Palestinians and Arab states.

"What was new and significant was the approach he took to the Israeli government," he said. "He not only called for the immediate implementation of the latest U.N. resolution calling for Israeli withdrawal and a cease-fire, he talked about settlements, he talked about an end to occupation."

Asked by a television interviewer if Mr. Bradshaw shared Mr. Bush's assessment that Mr. Arafat had failed, he said, "He has failed in the past, let's hope he succeeds now."

President Jacques Chirac, on the campaign trail for re-election in France, called Mr. Bush's speech a "true turning point."

"We are seeing the United States recommit itself," Mr. Chirac said, noting that America was indispensable to any agreement.

In Brussels, the European Commission president, Romano Prodi, pledged Europe's full cooperation in helping to obtain the withdrawal of Israeli troops from Palestinian towns and the establishment of a cease-fire. Before the speech, Mr. Prodi had been harshly critical of Israel's military incursion.

On Wednesday night, European Union foreign ministers meeting in Luxembourg called for an immediate withdrawal of Israeli troops, and dispatched top envoys to try to meet with Mr. Arafat.

José María Aznar, the Spanish prime minister and current holder of the European Union's rotating presidency, said that Prime Minister Sharon of Israel was "wrong" to block the meeting with Mr. Arafat. Mr. Sharon's action prompted the two European envoys to cancel talks with him and abruptly end their mission today.

Reuters news agency reported that Belgium's foreign minister, Louis Michel, argued in Luxembourg on Wednesday night that the 15 European Union nations should suspend Israel's preferential trade status, and that others proposed a tourist boycott.

Pope Paul II called on the Roman Catholic Church today to hold a world day of prayer Sunday for the Middle East where, he said, people are suffering "unprecedented violence." Warren Hoge

United Nations
Working to Force Israeli Withdrawal
Secretary General Kofi Annan said that President Bush's admonishment of Israel today was an important step, and he welcomed the impending visit of Secretary Powell to the Mideast.

"I think the announcement today was encouraging, and I have spoken to the secretary of state, and I am happy that the U.S. is becoming much more engaged," Mr. Annan said after a ceremony in which Germany presented the United Nations with three symbolic pieces of the Berlin Wall.

Mr. Bush's unequivocal call for an Israeli withdrawal unlocked a jam in the Security Council, which has been all but paralyzed for two days by Arab efforts to pass a resolution telling both Israelis and Palestinians to act on Resolution 1402, a measure passed last weekend. The earlier resolution called for an Israeli withdrawal from Palestinian towns and blamed both sides for the fighting.

For a week, the administration has been sending conflicting signals. American diplomats backed Resolution 1402, while the president appeared to hold the Palestinians largely responsible for the violence. But Mr. Bush's message was different today, and after his speech, the Arab resolution, which simply "demands the implementation of its Resolution 1402 without delay" and welcomes Secretary Powell's trip, passed 15-0 in the Council.

Speaking to the Security Council later, Mr. Annan had harsh words for the Israelis, saying that "self defense is not a blank check." He said that forcing Mr. Arafat into exile would be reckless and in violation of international conventions. But he also told the Palestinians not to hope that terrorism would bring down Israel. Barbara Crossette

Congress
Praising the President for Seeking Balance
President Bush's decision to put his administration at the center of new Middle East negotiations won wide praise today from members of Congress across the political spectrum, who said the escalating violence threatened vital American interests in the region. However, some conservatives, many of them outside of government, had been pushing for acceptance of Israel's use of force against Mr. Arafat.

Both of the Democratic leaders in Congress — Senator Tom Daschle, the majority leader from South Dakota, and Representative Richard A. Gephardt, the House minority leader from Missouri — rallied behind Mr. Bush. "After months of violence, this initiative is rightly focused on results." Mr. Daschle said.

An array of Republicans also praised the president. Senator Chuck Hagel, Republican of Nebraska, said the escalating violence was hurting the United States' standing in the world and that Israel's military incursion had backfired, making Mr. Arafat more relevant.

Representative Henry Hyde, Republican of Illinois and the chairman of the House International Relations Committee, emphasized the balance Mr. Bush had struck. "President Bush is making it clear that as Israel stops its incursions into Palestinian territories, there must a significant response from the Arab side," he said.

Just a day before Mr. Bush spoke, a number of conservatives had been pushing hard for the president to give Israel wide latitude to respond militarily to the wave of suicide bombings. Representative Tom DeLay, the House majority whip from Texas, had called Mr. Arafat "completely untrustworthy."

Some conservatives said the president may have simply deferred harder choices, and that the test would come when Israel withdraws from Palestinian-controlled territory. "What happens during that withdrawal?" asked Gary Bauer, who unsuccessfully sought the Republican presidential nomination in 2000. "Do 18-year-olds start blowing themselves up again? If they do, everything that can be said has been said, and it's time for a military solution to bring peace." Alison Mitchell