SEOUL, April 13 -- Actress and former After School member Nana has reportedly stood by her criticism of The Boyz's Sunwoo, after a viral video of the idol sparked controversy over his behaviour toward a security guard.

According to a report in The Korea Times, the footage, which circulated widely on social media, was said to show Sunwoo dropping his wireless earbuds and remaining still as a security guard picked them up and returned them using both hands.

Sunwoo reportedly accepts them with one hand, without bowing or visibly thanking the guard - a gesture netizens have called disrespectful.

"He needs to be scolded," Nana was reported to have commented under a post of the video.

In response to fan backlash, she later doubled down in a...