A manhunt has been launched to find a 14-year-old girl in “extreme danger” who is believed to have been abducted from her bedroom by a 33-year-old man, US authorities said.

An amber alert has been issued to find Isabel Shae Hicks and her suspected abductor Bruce William Lynch Jr.

According to a post by the Louisa County Sheriff’'s Office on Facebook on Sunday, Lynch may be carrying a handgun and has had suicidal thoughts. He is considered to be armed and dangerous.

Detective Chuck Love said Isabel was last seen by her sister in their shared bedroom in Bumpass, NBC reports.

The FBI said in a press statement that Isabel vanished at around 1am on 21 October.

Her sister woke up later that morning to discover her sister missing. She then told her parents who contacted the police.

During a press conference on 24 October, Isabel’s brother pleaded for her return, saying: “We miss you very much and we want you to come home. I love you forever.

“I just need my best friend back.”

The FBI, who is assisting in the investigation, has urged anyone who sees the pair not to approach but instead call authorities.

Lynch may be driving a light blue, silver looking, 2003 Toyota Matrix.

The rear passenger door handle is missing on the vehicle and it may have the Virginia tags VEM-9071, UXW-3614, and, or, a yellow “Don’t Tread on Me” tag.

Camping gear was also reported missing from Lynch’s home and it is believed the pair may be staying in areas suitable to camp, Detective Love told NBC.

The sheriff’s office said: “Information received appears they may be travelling out of state and staying in areas where they could camp.”

Lynch is described as a white male with brown hair, brown eyes, a beard weighing around 195 pounds (13st 9) and is 5ft 11.

Isabel is described as a white female with blonde hair, blue eyes, weighing around 120 pounds (8st 5) and is 4ft 11.