(Reuters) - The U.S. Justice Department filed a lawsuit on Monday against Southeastern Oklahoma State University over its suspected discrimination against a transgender assistant professor.

The DOJ said it also sued the Regional University System of Oklahoma. The department said the woman, Rachel Tudor, was denied a promotion because of her gender identity and retaliated against after she complained.

University officials were not immediately available for comment.

The complaint said Tudor, a male-to-female transgender who had taught in the English department, was terminated from the university in 2011 after the school denied her tenure.

"We will not allow unfair biases and unjust prejudices to prevent transgender Americans from reaching their full potential as workers and as citizens," Attorney General Eric Holder said in a statement.