Ahead of a summit this week with President Bush (search), South Korea's leader acknowledged minor differences with the United States on how to deal with North Korea's nuclear ambitions, but said the two allies were united on the principle of resolving the crisis peacefully.

Bush and South Korea's President Roh Moo-hyun (search) will almost certainly take a different tack than in 2001, when Bush and the previous South Korean president, Kim Dae-jung, met in Washington. That summit exposed sharp differences in how the two allies viewed communist North Korea.

Even though the policy differences remain, Bush and Roh are likely to reaffirm their military and economic partnership when they meet for the first time.

"Previous South Korea-U.S. summits have been burdened by high expectations," Roh told reporters on a chartered Korean Air passenger plane before arriving in New York on Sunday afternoon. "I hope the talks will confirm our common approach to resolving the PreNorth Korean nuclear issue, and also the importance of the South Korea-U.S. alliance."

Roh said the summit Wednesday won't yield "spectacular" results, and added: "On matters of detail, there are different points of view. But on the big matters of principle, we are in accord."

"The mere thought of a military conflict with North Korea (search) is a calamity for us," Roh told The Washington Times in an interview in Seoul on Friday. "If possible, we think it is much more reasonable for us to induce North Korea to reform itself and to open up to the outside world."

On Monday, Roh planned to visit the New York Stock Exchange and the World Trade Center site before heading to Washington on Tuesday.

The sense of urgency about North Korea's military threat is far greater now than when Kim met Bush and spoke in favor of engaging the North. Bush said at the time he didn't trust North Korea and would suspend missile talks with it, embarrassing the South Koreans and infuriating North Korea.

U.S. resolve has hardened in the wake of the Sept. 11 terror attacks and U.S. military campaigns in Afghanistan and Iraq. American officials say they want a peaceful end to the North Korean crisis, but some in the U.S. administration believe only a change of government in Pyongyang will fully resolve the problem.

Washington demands that North Korea abandon its nuclear programs, and the North says it will only do so in exchange for security guarantees and economic aid.

Tension over the nuclear dispute spiked last month during the Beijing talks, when, according to U.S. officials, North Korea claimed to have nuclear weapons and threatened to use or export them, depending on U.S. actions.

During the talks, U.S. officials said North Korea claimed it had reprocessed 8,000 spent nuclear fuel rods -- a move that could yield several atomic bombs within months.

Roh, on his first trip to the United States as president, said he would discuss ways the United States and South Korea can peacefully resolve the North's nuclear issue.

Roh visits as intelligence officials probe whether North Korea is manufacturing plutonium. The officials lack information because North Korea has expelled onsite nuclear inspectors.

Washington could eventually pursue economic sanctions against North Korea through the U.N. Security Council. The North has said such a step would amount to a declaration of war, and it would undermine the South's faltering efforts to reconcile with its neighbor.

On Sunday, North Korea warned that it would take "emergency measures" if the United States does not drop what it described as a hostile policy toward the communist country.

Further complicating matters, a key North strategy is to try to exploit any perceived rift between the United States and South Korea. Any sign of a rift also could embolden North Korea as it plots strategy.

The two leaders also are likely to discuss the 37,000 U.S. troops in South Korea, a legacy of the 1950-53 Korean War, as Washington considers the redeployment or reduction of forces abroad.

South Korea and the United States are "out of step" over when to pull back the 2nd Infantry Division from the DMZ, Roh said on television recently. But he said: "Some people seem to believe, 'If we don't have the U.S. military, we will all die.' That's simply not true."

The issue is sensitive in South Korea, where Roh drew electoral support from youths who staged demonstrations last year against the U.S. military after the deaths of two girls hit by a U.S. military vehicle.

But Roh opposes plans to pull U.S. troops back from the Demilitarized Zone separating the two Koreas, saying they should be a bargaining chip in any talks with North Korea on reducing its forces along the border.

Roh, who won the presidency partly by saying he wanted South Korea to be less reliant on the United States, will return to South Korea on May 17 after a stopover in San Francisco.