WASHINGTON -  

Labor Secretary Hilda Solis is telling colleagues she is leaving the Obama administration.

In an email message, Solis says she submitted her resignation letter to President Barack Obama on Wednesday afternoon. She says she made the decision to leave after discussing it with her family and close friends.

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.