WASHINGTON, April 24 -- As U.S. President Barack Obama's Asia tour this week aims to ease tensions between Japan and South Korea, it would not be easy to dial back ill feelings emerging from their differences on historical issues, some U.S. experts said.

Japanese Prime Minister Shinzo Abe put Tokyo at odds with Seoul in recent months after urging a revision to the Kono Statement - an apology released by then Japanese Chief Cabinet Secretary Yohei Kono for forcing Korean, Chinese and other countries' women to work as the comfort women in military-run brothels during World War II.

The territorial disputes over the islets, known as Dokdo in South Korea and Takeshima in Japan, also lies halfway between the two nations.

"(Obama) is going to have to explain this dynamic where we, the United States, need a good trilateral relationship - a good relationship between South Korea, Japan and the United States," Nicholas Hamisevicz, director of research at the Korea Economic Institute, told Xinhua in a recent interview.

Hamisevicz said that Obama would have to explain Washington's displeasure - in private, away from the cameras and media - and propose a set of solutions.

The U.S. embassy in Japan expressed its disappointment in December with Abe's visit to the Yasukuni Shrine, which honors Japan's war dead including 14 Class A WWII war criminals, saying it was "disappointed that Japan's leadership has taken an action that will exacerbate tensions with Japan's neighbors."

But that won't be easy. South Korea is an increasingly confident emerging power, with a highly emotional population irked by Abe's series of remarks and moves smacking of a throwback to Japan's brutal war regime.

Bruce Klingner, senior research fellow for Northeast Asia at The Heritage Foundation, told Xinhua that Abe's historical revisionist comments are the main driver of South Korea's response, which awakens bad memories of Japan's annexation of the Korean peninsula in the early 1900s.

"There's a long South Korean memory of the occupation and how brutal it was, and any sense that Japan is going back on the "Kono statement" triggers an immediate, strong and emotional response from South Korea," Klingner said.

South Korea has urged Japan to give up its claims on the disputed islets, provide compensation for the comfort women, and print textbooks that admit Japan's wartime aggression. But those are unlikely to occur anytime soon, Hamisevicz said.

As such, South Korea will have to decide which sort of compromises will bring about a satisfactory end to the tensions, he said.

"That's not going to happen by the time President Obama gets back to the United States," after his trip, Hamisevicz said.

Amid pressure from the United States and angry response from Japan's neighbors including South Korea and China, Abe later announced he would not seek to revise the statement.

Still, there have been some positive developments, such as Abe's recent confirmation of the 1993 apology after frank behind-the-scenes discussions with the United States, which enabled a trilateral U.S.-Japan-S. Korea summit in The Hague last month, Klingner said.