Iranian President Hassan Rouhani delivers a speech in Tehran, Jan. 17, 2016. The U.S. blames Iranian hackers for an attack on a dam north of New York City. Getty Images/Atta Kenare

U.S. officials are planning to publicly blame Iranian hackers for a 2013 cyberattack on a New York state dam, CNN reported Thursday. Hackers infiltrated the dam’s control system and, while they didn’t cause any damage, the incident created new levels of concern stretching to the White House, according to previous reports.

Justice Department officials have prepared an indictment against the Iranians suspected of launching the attack, according to CNN, and an announcement could come in the coming days. U.S. officials told the news network the attackers have ties to the Iranian government and used malicious software tools that are widely available for sale on online criminal forums.

The incident occurred at the Bowman Avenue Dam, located about 30 miles north of New York City in Rye, Westchester County. The White House was tipped off to the attack when officials initially believed it was targeting a more important dam in Oregon.

The attack came three years after the United States was blamed for launching the Stuxnet cyberattack, a digital espionage campaign launched with help from Israel. That attack, which caused physical damage to centrifuges at an Iranian nuclear facility, is widely seen as the first shot across the bow in what could become an international cyberwar.

The Iranian indictment is part of a broad U.S. strategy to publicly shame the attackers deemed responsible for major hacks. In 2014, the Justice Department unveiled indictments against five members of the Chinese People’s Liberation Army accused of infiltrating various American companies. Neither China nor Iran have extradition treaties with the U.S.