SEOUL, South Korea — The U.S. ambassador to South Korea called the Korean peninsula’s post-World War II division a great tragedy Wednesday, responding to heated criticism of America’s role in the breakup.

The United States and the former Soviet Union divided the peninsula into separate occupation zones in what was meant to be a temporary measure following Japan’s surrender in 1945, which ended 35 years of colonial rule by Tokyo. The current political form took shape in 1948 with the foundation of the Republic of Korea in the South and the rival Democratic People’s Republic of Korea in the North.

"The division of Korea was one of the great tragedies of the 20th century, and the division of Korea happened through no fault of the Korean people," Ambassador Kathleen Stephens told a meeting of the American Chamber of Commerce in Korea.

The comment was prompted by Chi Yang-chin, a professor emeritus in the social welfare department of South Korea’s Chung-Ang University. He launched into a lengthy criticism of the role played by the United States and the Soviet Union in the peninsula’s division.

"This is your responsibility," said Chi, a member of the chamber, adding the United States "should be responsible to unify this country." He called on Stephens to "reflect Korean opinion to the higher politicians in Washington."

South Korea and the United States have been close economic and security partners since the end of World War II. While South Koreans generally look favorably on their relationship with the United States, Chi’s comments underscore that some remain critical of Washington, seeing it as having had too much influence in the country and of being a hindrance to reunification of the North and South.

Unification is an emotional subject in both Koreas, and the peninsula is seen as having been long caught in the crossfire of the competing interests of stronger powers.

Chi described himself as a "victim of the Korean conflict," saying he was separated from his family. He said he would like "to see my country unified before I die."

Stephens said she appreciated "the passion" of his remarks. "It is a tragedy, I agree with you, that here in the 21st century we still have unfinished business, and that unfinished business is to achieve a Korean peninsula that is whole, free and at peace," she said.

Stephens said it was U.S. policy and "my deepest personal desire" to see the peaceful and democratic unification of Korea "on terms that are acceptable to the Korean people."