Superior Court Judge Mitchell Beckloff temporarily suspended Katherine Jackson as the children's guardian because she is in Arizona and hadn't spoken with them in several days. He appointed Tito Joe "TJ" Jackson to serve as temporary guardian with the ability to control the hilltop home where the children live and to take on other supervision duties.
Beckloff said there was no evidence that Katherine Jackson had done anything wrong but instead it appeared she was being prevented from fulfilling her role as guardian through the "intentional acts of third parties." He didn't elaborate.
He also said the children - Prince, Paris and Blanket - cannot be taken outside California without court approval.
The developments came after days of turmoil among the Jackson family that included a relative reporting Katherine Jackson missing before she was located safely with other family members in Arizona and an altercation between relatives on Monday.
Jermaine Jackson has said his mother was following doctor's orders to cut off communications with the children, who range in ages from 10 to 15. He didn't provide further details.
Katherine Jackson's lawyer, Perry Sanders Jr., said she had high blood pressure before she left for Arizona.
His co-counsel, Sandra Ribera, expressed concerned that Katherine Jackson may have been held against her will. She said one of the singer's children told her a conversation with the 82-year-old woman on Tuesday seemed to be monitored and influenced by others in the room.
Arizona authorities contacted Katherine Jackson on Sunday evening and it was determined she was safe, though her lack of communication with her grandchildren was described by TJ Jackson and others as unusual and unprecedented.
In addition to concerns about the safety of Jackson's children, some of Michael Jackson's siblings have recently called on the executors of his estate to resign.
Randy Jackson appeared Tuesday on Al Sharpton's MSNBC show PoliticsNation and said he believes his brother's will is a fake and that the executors have engaged in criminal activity.
The estate, which recently reported it saw $475 million in gross earning since Jackson's death in June 2009, has denied wrongdoing and called the accusations "false and defamatory."
The Jackson children have remained at the home they share with their grandmother in suburban Calabasas amid questions about Katherine Jackson's whereabouts and why she hadn't spoken with them since July 15.
Sheriff's deputies were called to the house on Monday after two factions of the family were involved in Monday's driveway confrontation. The incident remains under investigation.
Beckloff, who also oversees financial issues affecting Jackson's estate, was initially reluctant to appoint a temporary guardian but changed his mind after hearing from several attorneys who expressed concern about the family's problems.
TJ Jackson filed his petition under seal but appeared in court and was appointed temporary guardian after describing a "strange" conversation he had with Katherine Jackson on Tuesday evening.
"I've never heard my grandmother talk like that," he said reluctantly. "In every way. The sound in her voice. The pauses."
He said some of her speech sounded slurred and she used words that made him wonder if she was speaking in code.
The children's guardian ad litem, Margaret Lodise, said she spoke with the children and the two oldest, Prince and Paris, supported the appointment of a temporary guardian. Lodise did not ask the youngest son, 10-year-old Blanket, for his views.
Lodise is responsible for overseeing the children's interests in the estate of their father.
Beckloff ordered TJ Jackson's attorney Charles Shultz to give notice of his ruling to two other potential guardians - singer Diana Ross and Debbie Rowe, who is the mother of the eldest Jackson children. Ross was named in Michael Jackson's 2002 will as a potential guardian if his mother was not able to serve.
"Debbie is watching the situation carefully, and wishing for Katherine's speedy recovery," her attorney Eric George wrote in an email.
Schultz said TJ Jackson didn't want to replace Katherine Jackson as permanent guardian. Still, the judge noted that TJ Jackson would have to petition to become the permanent guardian within 48 hours and added that such a petition might not be heard if Katherine Jackson re-emerges.
Sanders said after the hearing that he had received word that she was returning Wednesday to Los Angeles. He said he would seek her reinstatement as guardian after speaking with her and would fight any move to have her permanently replaced.
He said he met with Randy and Janet Jackson in Tucson, Ariz., on Tuesday, but he was not allowed to see his client. He said he still hoped the recent events were a misunderstanding, but he described them as "chaos."