The K-pop group Kiss of Life is apologizing for all the distress a recent video they posted caused ... claiming they weren't trying to be racist while dancing to 50 Cent's "In da Club."

The band -- which boasts nearly 300K fans on X -- shared a handwritten apology Saturday admitting they erred by posting the recent birthday clip.

ICYMI ... the four bandmembers shared a clip where they danced to the hit 2003 track -- while wearing their hats askew and big gold chains around their necks, basically parodying clothing some rappers might wear.

While they seemed to mean their little dance as a joke ... many of their fans called them out for the behavior -- pointing out the parody is culturally appropriative.

In their apology, the Kiss of Life members -- Julie, Natty, Belle and Haneul -- apologize for posting the clip, adding it's been difficult to see how much they've hurt their longtime fans.

The ladies say they wanted to show how much they love hip hop ... but "ended up taking the concept too far" in the vid. They go on to say they realize the "content was culturally insensitive" and promise to do better moving forward.

They promise to continue to educate themselves ... and understand nothing they say or do will magically fix the damage they've already done.

While many of their fans seem eager to accept the apology ... others are still obviously upset -- posting about canceling the group on social media.