South Korea on Wednesday expressed understanding of U.S. President Barack Obama's upcoming visit to the Japanese city of Hiroshima despite concerns it could be interpreted as an apology for the atomic bombing that ended World War II.

On Tuesday, the White House announced that Obama will visit Hiroshima on May 27 together with Japanese Prime Minister Shinzo Abe to "highlight his continued commitment to pursuing the peace and security of a world without nuclear weapons."

Obama will become the first sitting American president to visit the city since the U.S. dropped a nuclear bomb there in August 1945.

"We understand that it was arranged under President Obama's vision for peace and safety through a world free of nuclear weapons," a Foreign Ministry official said on the condition of anonymity.

Washington has stressed that its position on the bombing has not changed and the visit will be used as an opportunity to mourn the victims, including more than 20,000 Koreans, according to the official.

The White House has made clear that the highly symbolic visit will not be an apology, saying Obama will offer a "forward-looking vision focused on our shared future."

South Korea, which suffered under Japanese colonial rule from 1910-45, has reacted angrily to Tokyo's attempts to whitewash its wartime atrocities. (Yonhap)