SPOILER: X Factor USA teen breaks down on stage (VIDEO)

A 13-year-old hopeful in American version of The X Factor has collapsed sobbing on stage after being knocked out of the contest, prompting concerns about exploitation of the young hopefuls.

Rachel Crow was sent home after judge Nicole Scherzinger refused to choose between her and Marcus Canty, deliberately sending the vote to deadlock - which revealed that the teenager had the fewest votes.

On hearing the bad news, the youngster slumped to the ground and dissolved into tears - prompting her mother to run on stage to comfort her.

Show host Steve Jones moved to comfort her but was beaten to the punch by head judge Simon Cowell, who shielded her from the cameras as he gave her a hug.

Rachel's was quickly on the stage reassuring her that everything was going to be okay, and between sobs Rachel could be heard replying: "Mommy you promise me?... Promise me?"

The lower age limit for the show in the US is 13, whereas in the UK it is 16.

See the unhappy moment for yourself...