Telecommunications company Ciena disclosed in its latest annual report that it has initiated an internal investigation into potential violations of the Foreign Corrupt Practices Act and voluntarily notified U.S. authorities.

“During fiscal 2017, one of Ciena’s third-party vendors raised allegations about certain questionable payments to one or more individuals employed by a customer in a country in the ASEAN region,” the company disclosed. Member states of the ASEAN region are Thailand, Vietnam, Indonesia, Malaysia, Philippines, Singapore, Myanmar (Burma), Cambodia, Laos, and Brunei.

Ciena said it “promptly initiated an internal investigation into the matter, with the assistance of outside counsel” and sought to determine whether direct and indirect payments made may have violated applicable laws and regulations, including the FCPA.

Ciena said it voluntarily contacted the Securities and Exchange Commission and the U.S. Department of Justice in September 2017 to advise them of the relevant events and the findings of Ciena’s internal investigation. With the direct oversight of the board, Ciena said it continues to cooperate fully with these agencies in their review of the investigation.