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Kevin Federline and his lawyer were in court Friday, reportedly to try to strip Britney Spears of her visitation rights after a three-hour child custody standoff ended with an apparently intoxicated Spears being taken to the hospital in an ambulance Thursday night.

Federline's lawyer, Mark Vincent Kaplan, headed into court Friday at about 11:30 a.m. EST to ask Los Angeles County Superior Court Commissioner Scott Gordon to take away Spears' visitation rights — at least for now, TMZ.com reported.

Kaplan and Spears' attorney, Tara Scott, met with the commissioner in a closed-door meeting for about 30 minutes. A court hearing was under way Friday at 5 p.m.; TMZ said Federline might testify.

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Kaplan scheduled a press conference Friday but later changed his mind. His spokesman, Michael Sands, said it would be "inappropriate for him to speak to the media ... because of what's happened last night, because of the serious nature of what we've all read about."

Sands said Kaplan had been at Cedars-Sinai Medical Center after Spears was admitted Thursday.

Police initially said it appeared the 26-year-old Spears was under the influence of an unknown substance, but Officer April Harding said she could not confirm that or other reports that Spears was hospitalized for mental evaluation.

"For her own welfare, she was transferred to a local hospital for medical treatment," Harding said early Friday.

As of Friday afternoon, Spears was reportedly at Cedars-Sinai Medical Center on a "5150 Hold," which means, according to the medical code, "When any person, as a result of mental disorder, is a danger to others, or to himself or herself, or gravely disabled." The "mobile crisis team" is able to make this recommendation in writing and take a patient be evaluated and treated.

A source told People magazine that Spears will be on a minimum 72-hour lockdown for mental evaluation.

Friends, Family Speak Out

FOXNews.com spoke briefly with a former dancer and friend of Spears, who said that the singer's behavior becomes more erratic around the time of court hearings and depositions.

"Britney is terrified of this, which is why she is always late or doesn't show," the source said. "She totally loses it, and with the depo and the media circus yesterday, she just couldn't handle it," the source added, referring to Spears' deposition in her custody battle on Thursday.

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The friend has not been able to reach Spears or her family since the incident.

The Spears pal also told FOXNews.com that Britney's breakdown was "no surprise" and that as much as he feels for her, he thinks that this all for the best.

"Fingers crossed she might now actually get the help she needs," said the source. "It was going to take something drastic like this before anything could be done."

A source reportedly told Us Weekly magazine that Spears was not under the influence Thursday night but suffering from mental problems, and was constantly being watched at Cedars-Sinai to make sure she would not harm herself.

The magazine quotes a source saying Spears went "completely psycho" as she was rushed to the hospital. "They had to strap her down like a mental patient and she was going between laughing and hysterics," the source adds, calling it "a total psychotic breakdown. She just went crazy."

While Spears' dad, Jamie, has been at Cedars-Sinai, mom Lynne is in Kentwood, La., with sis Jamie Lynn, reports "Access Hollywood."

"Just say prayers,” an audibly distraught Lynne told "Access" during a brief phone conversation Friday.

Meanwhile, Britney's brother Bryan was supposed to show up in L.A. Friday, reports People. The magazine's Web site quotes a source saying the family is "terrified" by all that's happened to Britney.

"Everyone has been worried for some time. Her world has been crumbling around her and this is another call for help. Her parents are just devastated. Nobody knows if they can take much more, but they're trying to be as strong as they can."

Cops, Ambulances Called

According to TMZ, Spears' youngest son, 1-year-old Jayden James, also was transported by ambulance for treatment following the standoff between Spears and employees of her ex-husband Federline at her California home.

Spears was said to have locked herself in the bathroom with Jayden James at her $4.5 million, five-bedroom, six-bathroom home in the Santa Monica Mountains above Beverly Hills.

A source told People magazine it was the pop star's court-appointed child monitor who called police.

"She had already put Preston in the car when Britney locked herself in a room with Jayden," says the source. "The cops came and got through the door and tied her down to a gurney."

Officers were called to Spears' house around 11 p.m. Thursday for an issue involving custody of Jayden James and 2-year-old Sean Preston, Harding said. By about 10:30 p.m., six police cars, two ambulances and a fire truck had entered the gated community.

Federline's bodyguards intended to collect the two toddlers at 10 p.m., but Spears reportedly refused to hand them back.

The singer turned over the children around 1:50 a.m., Officer Jason Lee, a police spokesman, told City News Service.

Around 3 a.m., a conscious Spears was wheeled out on a gurney, following hearsay that someone inside the home was in a hysterical, possibly intoxicated state. Britney appeared to be smiling and laughing when wheeled out of her home, a witness told FOXNews.com.

Aerial footage from KTLA-TV showed Spears being lifted on a gurney into an ambulance. The ambulance left her home escorted by a row of police cars.

Lee told the Associated Press that no injuries were reported, yet Spears was believed to be under the influence of an "unknown substance."

• Psychiatrist: Britney Can Get Better, Kids Need Immediate Stability

Cedars spokeswoman Simi Singer said she could not confirm or deny the report that Spears was at the hospital, citing patient confidentiality laws.

KTTV-TV, however, reported that Spears' father, Federline and friend Sam Lufti showed up at the hospital.

The incident involved a family dispute that police worked to resolve "peacefully by court order," Lee said.

FOXNews.com also has learned that Sean Preston was safely returned to Federline's guards just over an hour before Spears was wheeled from her home.

Custody Battle

Federline, 29, has temporary custody of the children because Spears, who has limited visitation rights, has defied court orders. The two were married in October 2004 and divorced in July.

Calls to attorneys for Federline and Spears were not immediately returned.

Earlier Thursday, the singer appeared for a deposition in the custody dispute. She was deposed for 14 minutes, Federline attorney Kaplan told reporters after she left.

• Report: Britney Spears Arrives Two Hours Late for Deposition

Spears called in sick for a Dec. 12 court-ordered deposition but was photographed that day driving with a friend. She also did not show up for a session Wednesday, Kaplan said.

Spears' attorneys from the firm Trope and Trope on Wednesday filed a court motion asking to be relieved due to a "breakdown" in communication with their client.

Kaplan said Spears' attorneys were present for what became a very abbreviated session.

"The deposition proceeding did go forward today (Thursday). It was scheduled for 9:45 to 11:45," Kaplan said. "However, it wasn't able to commence until 11:32. You can imagine in 14 minutes there's not a lot of time to develop questions," he said.

Kaplan said another deposition would be scheduled.

Over the last 13 months, Spears has been photographed without underwear and has appeared to be drunk and out of control. She shaved her head, beat a car with an umbrella and spent a month in rehab. She has also had a handful of fender benders, including one in which she ran over a photographer's foot.

Last month her sister, Nickelodeon's "Zoey 101" star Jamie Lynn Spears, 16, said she is pregnant.

Shortly after that announcement, a parenting memoir being written by the Spears sisters' mother, Lynne Spears, and set to be released by a Christian book publisher was delayed. "Pop Culture Mom: A Real Story of Fame and Family in a Tabloid World" was initially scheduled for release on May 11, Mother's Day.

Click here for Britney Spears' biography.

FOX News Entertainment Reporter Hollie McKay and the Associated Press contributed to this report.