Backstreet Boys singer Nick Carter has filed a restraining order against his pop star brother Aaron, alleging he threatened to kill his pregnant wife and unborn child.

Nick has been granted a temporary order saying Aaron must stay at least 100 feet away from him, his family and his home in Las Vegas.

Explaining his decision, Nick, 39, 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, acknowledged the restraining order on Twitter but denied the allegations of threatening behaviour.

He said: “I am astounded at the accusations being made against me and I do not wish harm to anyone, especially my family.”

Aaron, who rose to fame in the late 1990s as a child singer, 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 and announced wife Lauren was expecting the couple’s second child in May.