South Korean survivors of the atomic bombing of Hiroshima are urging U.S. President Barack Obama to apologize for the suffering caused by that "horrific crime" against humanity when he makes his historic visit to the Japanese city later this month.

In a letter addressed to Obama, the Association of Korean Atomic Bomb Victims asked him to "offer an apology" when he visits the Hiroshima Peace Memorial Park on May 27 after the summit of the Group of Seven nations in Mie Prefecture.

Obama was also urged to visit a monument in the park that is dedicated to the tens of thousands of Koreans who were living in the city when the tragedy occurred on Aug. 6, 1945.