UniCredit, Italy’s largest bank by asset s, is being investigated by US authorities for possibly breaking sanctions that prohibit doing business with certain countries, according to documents published by the bank.

While the documents do not mention a particular country, a person familiar with the situation said the investigation involved Iran. Although UniCredit first disclosed the investigation by US authorities at least seven months ago, it appears never to have been reported in the media.

UniCredit is being probed by the New York County District Attorney’s Office and the US Treasury Department’s Office of Foreign Assets Control, according to the documents. The US Department of Justice is also investigating, UniCredit said in a statement at the weekend.