California Attorney General Kamala Harris announces US Senate bid
California Attorney General Kamala Harris addresses the second session of the Democratic National Convention in Charlotte, North Carolina, in this file photo taken September 5, 2012. REUTERS/Jason Reed/Files

California Attorney General Kamala Harris, a rising star in the Democratic Party, said on Tuesday she would seek the U.S. Senate seat being vacated in 2016 by Barbara Boxer, who will retire after 33 years in Congress.

Harris' bid, announced online, sets up the prosecutor as a strong contender in a rapidly growing field of potential candidates.

"I will be a fighter for the next generation on the critical issues facing our country," Harris said in the announcement. "I will be a fighter for middle-class families who are feeling the pinch of stagnant wages and diminishing opportunity."

Boxer's departure, announced last week, is the first of three anticipated retirements among California's top leaders that should clear the way for a younger generation of politicians who have been waiting in the wings.

Governor Jerry Brown, 76, will leave office at the end of his fourth term in 2018 because of term limits. U.S. Senator Dianne Feinstein, 81, will be 85 when her term ends.

California Lieutenant Governor Gavin Newsom, whose support for same-sex marriage while mayor of San Francisco spurred a wave of social and political change, said on Monday he would not run.

His announcement leaves the field open to potential candidates including Harris, 50, and former Los Angeles Mayor Antonio Villaraigosa, 61, both Democrats.

Harris, like Newsom, rose from the San Francisco political scene and is a former district attorney who has used her position to develop policy ideas as well as handle prosecutions.

Now in her second term as Attorney General, Harris drew national attention as a tough negotiator after the U.S. mortgage meltdown, when she pushed for and won concessions from major banks in a nationwide settlement aimed at helping consumers who had lost their homes to foreclosure.

Harris also sponsored the state's Homeowners Bill of Rights, which sets rules for foreclosures.

She has focused on numerous social issues, including human trafficking, international gangs, and school truancy.

Of African-American and South Asian descent, Harris is the daughter of two college professors and grew up in the Bay Area during the civil rights turmoil of the 1960s.

(Additional reporting by Alex Dobuzinskis in Los Angeles and Curtis Skinner in San Francisco; editing by Gunna Dickson)