A pop group has flown back to South Korea after officials in Los Angeles thought they might be sex workers.

The eight members were travelling to America for an album cover shoot but were detained for 15 hours in customs.

A statement from the group's record company, WM Entertainment, said authorities held them after going through their costumes and props.

"They seem to have mistaken them as sex workers," said a spokesman.

Oh My Girl, who formed in March, are thought to be back in South Korean capital Seoul after being released by officials at Los Angeles International Airport.

WM Entertainment says it is taking legal advice in the US to find out whether the band's detention was legal.

The record company also said there might have been an issue with the type of visa the band members presented.

They had also been booked to perform at a gala event in Los Angeles on Saturday.

It's unclear if they will try to return to America to complete their album cover shoot.

Oh My Girl (or OMG) brought their debut single Cupid out in April with a second mini-album and title track Closer released in October.

The band members are all aged between 16 and 21.

South Korean pop music, known as K-pop, is dominated by girl and boy bands whose members are sometimes as young as 13 or 14 years old.

In 2012, the government clamped down on over-sexualised performances by threatening to give higher age ratings to films, music videos and TV shows which exaggerated the sexuality of younger singers and bands.