DETROIT (AP) — Uber's chief human resources officer has abruptly stepped down.

Liane Hornsey told employees in an email Wednesday that she is leaving the company but gave no reason. The email was obtained by The Associated Press.

Hornsey writes that employees may think the decision came out of the blue, but she has been thinking about leaving for a while. The company would not comment on the reason for her departure.

CEO Dara Khosrowshahi (Cause-row-SHAH-hee) praised Hornsey in an email for releasing the company's first diversity report and ushering in equal pay for all employees. She's been with the company since January of last year.

Hornsey did not immediately return a telephone message Wednesday from The Associated Press.