Sowon, a member of the female band GFriend, was shown cuddling the mannequin in now-deleted photos that were taken in late 2020 while the group were filming a video in the South Korean city of Paju.
Her management agency said the singer had removed the post from Instagram as soon as she “understood the significance of the image”.
Source Music said in a statement that Sowon, 25, had been “very shocked” by the association with nazism, adding: “She is pained and feels deep responsibility for posting such image.”
The agency said: “We want to apologise for not being able to check for inappropriate props in the set and not being able to thoroughly filter them during the shoot and uploading and failing to give detailed attention to historical facts and linked social issues. We bow our head in apology for causing offence through the video and stills.”
Sowon, who has more than 800,000 followers on Instagram, is not the first K-pop star to have drawn criticism over the use of Nazi insignia.
The Simon Wiesenthal Center, a Jewish human rights organisation, accused the group of “mocking the past” and noted that the artists had also posed at the Holocaust memorial in Berlin.
Another BTS member wore a T-shirt that appeared to celebrate the atomic bombings of Japan, which had ruled the Korean peninsula as a colonial power from 1910 until the end of the second world war.
Big Hit Entertainment said it “had no intention of causing distress or pain” to those affected by the nuclear attacks on Hiroshima and Nagasaki days before Japan’s surrender on 15 August 1945 – a date Koreans mark as their liberation from Japanese rule.