Aaron Carter has repeated rape and assault allegations against his brother Nick in a furious Twitter rant - after the Backstreet Boys singer filed a restraining order against him.

Nick announced he and his sister Angel had filed for a protection order against the Crazy Little Party Girl singer on Tuesday, alleging Aaron had made threats against his pregnant wife, Lauren Kitt, and their unborn child.

"In light of Aaron's increasingly alarming behavior and his recent confessions that he harbours thoughts and intentions of killing my pregnant wife and unborn child, we were left with no choice but to take every measure possible to protect ourselves and our family," he tweeted.

In response, Aaron, who was recently diagnosed with several mental health illnesses, including schizophrenia and anxiety, and scrapped an upcoming tour, furiously aired old allegations aimed at his brother.

"Anybody who knows me knows I wouldn't hurt a fly. I've never been accused of rape. I've never been accused of beating @ParisHilton how am I the violent one," Aaron shared on Wednesday morning.

When Nick and Paris dated in 2004, there were rumours he had caused bruises on the reality TV star's body. Former Dream singer Melissa Schuman also accused Nick of raping her in 2002 in an online blog back in 2017. The singer has denied both allegations - and a case filed by Schuman was dismissed last year.

Aaron continued to claim Nick filed the restraining order against him because he previously appeared on an Instagram live stream with Schuman, adding: "How come my brother didn't file a restraining orders against a girl who filed a police report against him for rape? #COVERUP #METOOMOVEMENT. #CoverUp I'm here for all of you girls. #MeTooMovement #Metoo."

The star went on to share a number of tweets from other users, also labelling his sibling a "rapist", before calling for an "R. Kelly-type documentary" to expose his brother.

Nick is yet to respond to Aaron's tweets.