Backstreet Boys singer Nick Carter has obtained a restraining order against his younger pop star brother Aaron, alleging he threatened to kill his pregnant wife and unborn child.
Nick, 39, posted a statement on social media saying he had been left with "no choice" but to take action, citing his brother's "increasingly alarming behaviour".
Aaron, 31, who had hits including Crush On You and Crazy Little Party Girl as a child star in the late 1990s, tweeted: "So my brother just got a restraining order against me. And I was just served lol."
The temporary order states that Aaron must stay at least 100ft (30 metres) away from Nick, his family and his home in Las Vegas.
Aaron has denied allegations of threatening behaviour.
In his statement, Nick said: "After careful consideration, my sister Angel and I regret that we were required to seek a restraining order against our brother Aaron today.
"In light of Aaron's increasingly alarming behaviour 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.
"We love our brother and truly hope he gets the proper treatment he needs before any harm comes to himself or anyone else."
Aaron, 31, said on Twitter: "I am astounded at the accusations being made against me and I do not wish harm to anyone, especially my family."
He added: "Take care. @nickcarter. we're done for life."
Aaron has a history of drug convictions and mental health issues. On a recent episode of US TV show The Doctors, he said he suffered from "multiple personality disorder, schizophrenia, acute anxiety and manic depression".
He later said he did not have any mental health issues and the show had been edited to make it look like he did. The Doctors' producers denied the episode had been edited.
Nick is a member of chart-topping boy band the Backstreet Boys, who had hits including Everybody, As Long As You Love Me and I Want It That Way in the 1990s.
He and his wife Lauren announced they were expecting their second child in May.
© Sky News 2019