A US judge has awarded sole custody of Britney Spears' two children to ex-husband Kevin Federline and suspended the singer's visitation rights.
The court in Los Angeles issued the ruling after Spears was arrested and stretchered away from her home by ambulance earlier today after refusing to hand her children over to Federline.
A four-hour standoff at the troubled singer's Beverly Hills mansion began at 7pm on Thursday (0300 GMT) when she refused to hand her sons, two-year-old Sean Preston and one-year-old Jayden James, over to the children's father.
Police officers arrived at Spears' home at around 8pm. She finally turned over the children at around 10.50pm, according to the Los Angeles police department.
Spears was taken to the Cedars-Sinai medical centre, where she has been visited by her father, Jamie, according to US entertainment websites.
Us magazine and the celebrity gossip website TMZ also claimed her younger son was taken to hospital at the same time in another ambulance.
The magazine reported that Spears had been designated as a "special needs" patient - a term given to those who "have either overdosed or tried to commit suicide".
TMZ said she was being held on a "5150 hold", meaning she is considered a risk to herself or others.
The hospital has refused to comment, citing patient confidentiality laws.
Six police cars, a police helicopter and a fire truck were called to the incident at the singer's home.
Aerial footage from KTLA-TV showed Spears being lifted into an ambulance on a stretcher. She was taken to hospital to be tested for both drink and drugs.
The LAPD officer Jason Lee told the City News Service that Spears was under the influence of an unknown substance. He added that no one was injured.
The incident involved a family dispute that police worked to resolve "peacefully by court order", he said.
TMZ reported that Federline's lawyer was going to court to ask the superior court commissioner to strip Spears of her visitation rights.
Spears and Federline, who were married in October 2004 and divorced in July 2006, were fighting over custody of their sons. Federline, 29, had previously been awarded temporary custody because Spears - who has limited visitation rights - has defied court orders.
The incident that led to police being called began when Spears refused to obey the court order and would not let the court-appointed monitor into her home.
She also refused to allow Federline's two bodyguards into the house when they arrived to take the children just before 8pm.
Her soon to be former lawyer, Sorrell Trope, told Us magazine: "In a normal case when someone shows up with a certified court order saying kids need to be somewhere else, the police see to it that the order is obeyed. But that is in a normal case."
Earlier yesterday, Spears arrived 90 minutes late for a deposition in her custody case at Federline's lawyer's office. She stayed for only a few minutes.
Today's incident is the latest in a string of scandals to hit the troubled pop star.
Spears reportedly checked into rehab in February last year, checking out again within 24 hours.
The following night, she went to a Los Angeles hair salon and shaved her hair off with clippers, prompting psychologists to declare her "disturbed".
In October, Spears was ordered to relinquish custody of her sons because the superior court commissioner said she was a "habitual, frequent and continuous use of controlled substances and alcohol".
She was allowed to see her children only if a monitor was present, and the visits could be cut short if the monitor decided Spears' behaviour endangered the them.
The singer was also ordered to undergo random drug and alcohol testing twice a week.
A few days later, she was officially charged with misdemeanour hit-and-run and driving without a licence, which was later dismissed.
After taking her case to the high court, the star won modified visitation rules that allow her two boys to spend one night a week with her.
Spears still faces a misdemeanour charge of allegedly driving without a valid licence.