President Bush intends to use his first extended tour of the Middle East to rally support for international pressure against Iran, even as a recent U.S. intelligence report playing down Tehran's nuclear ambitions has left Israeli and Arab leaders rethinking their own approach toward Iran and questioning Washington's resolve, according to senior U.S. officials, diplomats and regional experts.

Bush is to leave Tuesday for Israel, where he hopes to jump-start the Israeli-Palestinian peace negotiations he launched in Annapolis late last year. But in Jerusalem and some of the Arab countries Bush plans to visit, Iran's growing regional influence looms larger than the peace process or the Iraq war. Leaders in the region are gauging whether the lame-duck administration has the interest and ability to cope with Iran, or whether they should pursue their own military and diplomatic solutions.

"Part of the reason I'm going to the Middle East is to make it abundantly clear to nations in that part of the world that we view Iran as a threat, and that the [National Intelligence Estimate] in no way lessens that threat, but in fact clarifies the threat," Bush said in an interview with the Israeli newspaper Yediot Ahronot released Friday.

Administration officials have been alarmed by what they see as Iran's efforts to develop a nuclear weapon and intimidate its Sunni neighbors. But their efforts to build support for sanctions and other pressure on Tehran took a serious hit last month when a National Intelligence Estimate -- representing the shared view of U.S. intelligence agencies -- concluded that Iran halted its nuclear arms program in 2003.

Administration officials insist that the estimate showed Iran remains capable of, and interested in, developing a nuclear weapon. But Israel, which is believed to have nuclear weapons, saw the report as a sign that Washington is flagging in its zeal to confront Iran, which they regard as a threat to its existence. And in Arab Sunni countries such as Saudi Arabia, which feel threatened by the rising Shiite power that Iran represents, the NIE renewed doubts over whether the United States might be seeking an accommodation with Tehran.

In an interview yesterday, Arab League Secretary General Amr Moussa cited recent overtures between Iran and Arab countries and said Arab nations are exercising a prerogative to set their own course on Iran. "As long as they have no nuclear program . . . why should we isolate Iran? Why punish Iran, now?" he asked.

One senior administration official who spoke on condition of anonymity because he is not authorized to speak publicly about the trip said many Middle Eastern governments were "confused" by the NIE. "No Arab regime understands why the United States would publish an intelligence estimate." The official said Iran will be an important focus of Bush's conversations with regional leaders, with the president seeking to reassure them of U.S. staying power in the Middle East.

"Iran, for Israel, is topic Number One," said Meir Javedanfar, an Iranian expatriate living in Israel who runs an economic and political analysis company, and has written a book about Iran's nuclear program. "Most of the Israeli politicians and population see Iran as a greater threat than Hamas," he said, comparing Iran to the Islamic movement that controls Gaza. "And the Israeli government will be eager for Bush to show them that he is still committed to stopping Iran."

In Tehran yesterday, an Iranian government spokesman said Bush had failed to create an anti-Iran coalition. "The aim of these repeated trips is to compensate for the failed policies of America in the region," said Foreign Ministry spokesman Mohammad Ali Hosseini, according to wire reports.

Bush is planning stops in Israel, the Palestinian territories, Egypt, Saudi Arabia and several smaller Gulf countries during his eight-day trip. While in Kuwait, Bush will meet for the first time in four months with Gen. David H. Petraeus, the top U.S. commander in Iraq, and U.S. Ambassador Ryan C. Crocker, to discuss Iraq.

In Israel, which he is visiting for the first time as president, Bush is likely to be greeted as one of the country's greatest friends. But in the Arab world, his presidency has been perceived as damaging to the region and to U.S. prestige.

The overthrow of Saddam Hussein's Sunni Arab regime in Iraq, which long served as a counterweight to Shiite Muslim Iran, has allowed Iran's influence to grow. At the same time, Arab leaders blame the breakdown, until recently, of Israeli-Palestinian talks on Bush's refusal to assume the U.S. president's traditional hands-on role in Middle East peace negotiations.

Arab dissidents were elated and then devastated when Bush called for democracy in the region in 2005, only to appear to back away after election victories in Iraq and the Palestinian territories by religious blocs -- the only groups that had built popular support under autocratic governments. Bush plans to offer something of a report card on his Middle East "freedom agenda" when he stops in the United Arab Emirates' capital, Abu Dhabi, next week.

In Arab streets, many blame Washington for the plight of Iraqis and Palestinians. Bush's presidency has been "disastrous," said Hisham Kassem, an Egyptian journalist who received a National Endowment for Democracy award from him last fall. "America's neither feared nor loved. It's neither feared by the regimes anymore, and it's hated by the people of the Middle East. . . . That's the Bush legacy."

Complicating matters has been the effort by Iranian President Mahmoud Ahmadinejad, buoyed by soaring oil revenues, to expand Tehran's clout. The United States also sees Iranian meddling in Lebanon and Palestinian affairs through ties to Hezbollah and Hamas. But many Arabs blame U.S. actions for Iran's influence. In Iraq, where the 2003 U.S. invasion led to a Shiite government, "Iran got the best help" possible from Washington, Moussa said.

In December, Ahmadinejad scored a diplomatic trifecta: He spoke before the Gulf Cooperation Council, an Arab bloc formed to counter Iran, in the first such appearance by an Iranian president. He also visited Mecca for the haj religious pilgrimage at the invitation of Saudi King Abdullah, another first for an Iranian president.

Ahmadinejad closed the year by sending envoy Ali Larijani to Egypt, a country that has frozen ties with Iran for 28 years, offering to help Cairo develop nuclear energy. Talk of resuming diplomatic relations followed.

The challenge for Bush, according to analysts in Washington and the Middle East, is to convince Arab countries that their best hope for minimizing the Iranian threat is to stick with the United States -- while dissuading Israel from a unilateral, preemptive strike on Tehran's nuclear facilities.

"The real question is what can the president say or do to reassure them about Iranian power?" said Richard N. Haass, a former senior State Department official and president of the Council on Foreign Relations.

Bush's key stop may be in Riyadh, where Bush will hold a rare face-to-face meeting with King Abdullah, who has been alternately critical and supportive of U.S. efforts on Iraq, Israeli-Palestinian talks and the rest of the Middle East. The Saudi royal family, which rules in alliance with hard-line Sunni clerics, is concerned about the spread of Iranian influence and is unhappy with the new Shiite dominance of Iraq.

But Abdullah prefers to co-opt enemies, not confront them, and appears to be seeking a deal with Ahmadinejad, said Bruce Riedel, who worked on Middle East affairs in the Clinton and Bush administrations. "I think there is a great effort on both Riyadh and Washington's part to obscure that because they do not want the public spat," he said.

The senior U.S. official was skeptical, saying that the Saudis do not invite the Iranian president to their meetings -- "he invites himself."

"They are going to have a relationship with Iran," this official said. "Saudi diplomacy is traditionally quite cautious and conservative, but don't mistake caution and conservatism for sympathy."

But some Arabs suspect the Bush administration may decide it has to work with Iran to preserve security gains in Iraq. Khalid al-Dakheel, a political scientist at King Saud University in Riyadh, said "some people here think, or have the jitters, that this administration or the next administration . . . might find themselves in a position to reconcile themselves with the Iranians."