WASHINGTON — World leaders impatient for a new direction for America greeted President Obama's arrival with exuberance Tuesday but sent telltale warnings of the challenges about to envelop the new chief executive and his administration.
The White House was flooded with leaders' best wishes, including those of Pope Benedict XVI, who urged Obama to be "the promoter of peace and cooperation between nations."
At the same time, many of the messages were laden with hints of the caution required in dealing with the troubled times ahead. German Chancellor Angela Merkel, a conservative who had a good relationship with President Bush, nevertheless said she hoped that in the new era there would be agreement that "no single country can solve the problems of the world."
Obama, in a nod to the global sentiment and with Bush seated only a few feet away, left no doubt in his inaugural address that an important part of his audience was on the far side of the horizon.
He promised a new era of American leadership, suggesting that the Bush presidency, with too great a reliance on force, had veered from the U.S. approach that had won World War II and the Cold War.
"Recall that earlier generations faced down fascism and communism not just with missiles and tanks, but with sturdy alliances and enduring convictions," he said, a blunt repudiation of his predecessor that seemed to herald a return to earlier periods of American foreign policy. "We are ready to lead once more."
U.S. allies in Europe hope that the arrival of the new president will bring them closer to Washington on difficult issues -- such as dealing with international extremism -- and mean greater reliance on collective action and international institutions.
Governments showed they were eager to start the new relationship off on the right foot: Israel withdrew tanks and troops from the Gaza Strip, Russia resumed disputed gas exports to Ukraine, and South Korea sent a peace delegation to the North.
A senior European diplomat said recently that allies expect real benefits from the Obama glow, even if it is, in some respects, a will-o'-the-wisp.
"All expect this to give a boost to relationships with America and a boost to our joint efforts on our principal challenges," the diplomat said.
Even if Obama's foreign policy remains like Bush's in some ways, there will be "a change of tone, a new urgency," the official said. "That will make a difference."
International diplomacy has been in a state of suspension in recent months as some world leaders, weary from their struggles with the Bush administration, have awaited the new leadership.
Iran and North Korea have slowed negotiations over their disputed nuclear programs, hoping that a president who promised greater engagement will offer terms more to their liking.
One of Obama's first challenges will be to improve relations with the Muslim world, a task that has grown far tougher because of accusations that he remained silent as more than 1,300 Gazans were killed during Israel's just-ended three-week offensive.
Obama vowed "mutual interest and mutual respect" in dealing with the Muslim world, but he also warned violent extremists that "we will defeat you."
He ruled out the use of harsh detention and interrogation techniques and did not outline a future role for Bush's initiative to promote democracy, which many critics considered a pretext for American meddling.
Aides said Obama would demonstrate his intention to get right to work on Arab-Israeli issues by appointing former Senate Majority Leader George S. Mitchell as high-level envoy to the Middle East.
Mitchell, who is of partly Lebanese ancestry, is a former judge who served as a Mideast envoy during the Clinton administration. Officials hope his appointment will be read as a signal of a more sympathetic attitude toward the Arab world.
Israelis, who rely on U.S. backing, were effusive in their welcome and also indicated that they could adjust to even a major change in policy from the new administration.
Israeli President Shimon Peres said Israel wouldn't be alarmed if the Obama administration opened a dialogue with Iran as well as with Hamas, the Palestinian militant group that controls Gaza. But he predicted that doing so would be fruitless.
"He wants to build and make peace; they want destruction and war," Peres said.
A move to engage Hamas would be a sharp departure for the United States, which under Bush has had no contact with the group.
Nabil abu Rudaineh, spokesman for Palestinian Authority President Mahmoud Abbas, said Obama called Abbas after the election with two messages: "He's not going to waste time, and his slogan is 'change.' We're looking for a change in the direction of American policy in the Middle East. America needs to be fair and to tell each side when it is acting wrong and when it is acting right."
In Tehran, an advisor to President Mahmoud Ahmadinejad said the Iranian president planned to ignore televised coverage of the inauguration.