St. Louis ? The federal government Wednesday sued Walgreen Co., alleging widespread racial bias against thousands of black workers throughout the nation’s largest drugstore chain.

The U.S. Equal Employment Opportunity Commission alleged in a class-action lawsuit that Walgreen, based in Deerfield, Ill., makes decisions about employee assignment and promotion based on race.

Most of the complaints that led to the lawsuit, filed in U.S. District Court in East St. Louis, Ill., came from employees and former employees in St. Louis, Kansas City, Detroit and Tampa, Fla. But EEOC officials in St. Louis said they have found evidence of the same trend around the country.

Walgreen released a statement saying it is committed to “fairness, diversity and opportunity” and that it was “saddened and disappointed” by the EEOC action.