LOS ANGELES (AP) — An adviser with knowledge of her plans says California Attorney General Kamala Harris will announce Tuesday that she will seek the U.S. Senate seat being vacated by Sen. Barbara Boxer.

The disclosure comes after California Lt. Gov. Gavin Newsom said Monday he won't run for the open U.S. Senate seat created by Boxer's retirement next year.

The adviser was not authorized to discuss Harris's plans and spoke only on the condition of anonymity.

Former Los Angeles Mayor Antonio Villaraigosa and billionaire Tom Steyer are also considering bids for the seat.

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