The flagging state of U.S.-South Korean relations was reportedly highlighted earlier this month, when a Japanese official told visiting Korean lawmakers the United States might not trust their government.
Japanese Vice Foreign Minister Shoto Yachi was quoted as saying Tokyo was cautious about sharing North Korea-related intelligence with South Korea, because Washington - their mutual ally - did not trust Seoul.
Ambassador Lee Kyu-hyung of South Korea's Foreign Ministry says Seoul has strongly protested Mr. Yachi's remarks.
"It is not appropriate for the Japanese vice minister to mention Korean-American relations, and also our policy towards North Korea, which might cause unnecessary misunderstanding," the ambassador said.
Mr. Lee says that when the two presidents meet on June 10, Seoul hopes they will have "candid and comfortable" talks about the state of the alliance.
South Korea's approach of reconciliation and cooperation with the North differs sharply in both style and substance from the approach of Washington, where President Bush recently referred to North Korean leader Kim Jong Il as "a dangerous man" and "a tyrant."
Leaders in Washington have also expressed confusion at President Roh's stated ambition for South Korea to become a "balancing power" in Asia - a role that seems to imply a more neutral stance between the United States and North Korea.
Whatever differences may exist, Seoul and Washington say they cannot tolerate possession of nuclear weapons by the North.
Mira Sun, a Spokeswoman for President Roh, says Pyongyang's nuclear programs will be high on the summit agenda.
Ms. Sun says the two leaders will discuss ways of resolving the issue of North Korea's nuclear weapons programs peacefully and diplomatically.
Next month will mark one full year that Pyongyang has boycotted six-party talks on its nuclear weapons. Since abandoning the talks, North Korea has declared itself a nuclear state, and says it plans to add to an already existing nuclear arsenal - despite previous international pledges to remain free of such weapons.
South Korea's unification minister, Chung Dong-young, says getting the North back to the talks will be a priority during inter-Korean talks scheduled in Seoul next month, just days after the Washington summit.