Mariah Carey's sister is suing the US singer for $1.2m (£875,000) for "immense emotional distress" she says was caused by remarks in her memoir.

In the book, the diva made claims about her older sibling Alison's behaviour, including that she put Mariah at risk of being pimped out when she was 12.

Alison denied the claims, saying Mariah "presented no evidence to substantiate these serious allegations".

She said the "outrageous" material was meant to "humiliate and embarrass" her.

She is now seeking damages for the "heartless, vicious, vindictive, despicable and totally unnecessary public humiliation".

The memoir, titled The Meaning of Mariah Carey, was published in September. Alison Carey's two-page legal complaint was filed at New York Supreme Court on Monday.

In it, Alison accused Mariah of using "her status as a public figure to attack her penniless sister, generating sensational headlines describing her lurid claims to promote sales of her book".

She also says she is severely depressed due to the "unspeakable trauma of her childhood and having her own children abandon her". In the book, Mariah describes her sister as a "deeply wounded" person.

The BBC has asked Mariah's representatives for a comment.