WASHINGTON – Labor Secretary Hilda Solis resigned her post on Wednesday, saying she plans to return to her native California.

She is expected to run for a seat on the Los Angeles County Board of Supervisors.

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In a message to colleagues, Solis said she made the decision to leave after discussing it with her family and close friends.

One of the highest-ranking Hispanics in Obama’s administration, Solis has won praise from labor unions for aggressive enforcement of wage and hour laws and job safety regulations. But business groups have criticized her as not taking a more cooperative approach.

“Leaving the department is one of the most difficult decisions I have ever made, because I have taken our mission to heart,” Solis said.

“As the daughter of parents who worked in factories, paid their union dues and achieved their goal of a middle-class life, and as the first Latina to head a major federal agency, it has been an incredible honor to serve.”

President Obama called Solis “a tireless champion for working families.”

Separately, the White House said on Wednesday that Attorney General Eric Holder, Health and Human Services Secretary Kathleen Sebelius and Veterans Affairs Secretary Eric Shinseki would continue in their positions.