U.S. police are searching for Katherine Jackson, the mother of pop icon Michael Jackson, after her grandchildren were unable to get in touch with her for a week and a missing person's report was filed Saturday night, CNN reported on Sunday.

The 82-year-old matriarch of the Jackson music family left her Calabasas, California, home on July 15, to fly to Albuquerque, New Mexico, to attend a Jackson brothers concert two days later, CNN quoted Jackson's lawyer Sandra Ribera as saying.

Ribera believes Jackson may be with her oldest daughter Rebbie Jackson, with whom she left for Albuquerque.

However, when Paris, Michael Jackson's 14-year-old daughter, called Rebbie Jackson and another aunt, singer Janet Jackson, over the past several days, she was told each time she could not speak to her, Ribera said.

"The kids were trying to get a hold of their grandmother and they haven't been able to reach her for almost a week," Ribera said. "They are told she's unavailable."

"I'm concerned that she's not safe," Ribera was quoted as saying.

Jackson is currently in the midst of a dispute between several of her children and her advisers over her finances and legal affairs.

Jackson has not called Michael Jackson's three children, who have lived with her since their father died three years ago, Ribera said, adding the sheriff's robbery-homicide unit has been asked to investigate.